diff --git a/src/java/org/apache/poi/ss/formula/atp/AnalysisToolPak.java b/src/java/org/apache/poi/ss/formula/atp/AnalysisToolPak.java
index ad9604d9c..66ca17ddd 100644
--- a/src/java/org/apache/poi/ss/formula/atp/AnalysisToolPak.java
+++ b/src/java/org/apache/poi/ss/formula/atp/AnalysisToolPak.java
@@ -28,6 +28,7 @@ import org.apache.poi.ss.formula.functions.Dec2Bin;
 import org.apache.poi.ss.formula.functions.Dec2Hex;
 import org.apache.poi.ss.formula.functions.Delta;
 import org.apache.poi.ss.formula.functions.EDate;
+import org.apache.poi.ss.formula.functions.EOMonth;
 import org.apache.poi.ss.formula.functions.FactDouble;
 import org.apache.poi.ss.formula.functions.FreeRefFunction;
 import org.apache.poi.ss.formula.functions.Hex2Dec;
@@ -117,7 +118,7 @@ public final class AnalysisToolPak implements UDFFinder {
         r(m, "DURATION", null);
         r(m, "EDATE", EDate.instance);
         r(m, "EFFECT", null);
-        r(m, "EOMONTH", null);
+        r(m, "EOMONTH", EOMonth.instance);
         r(m, "ERF", null);
         r(m, "ERFC", null);
         r(m, "FACTDOUBLE", FactDouble.instance);
diff --git a/src/java/org/apache/poi/ss/formula/functions/EOMonth.java b/src/java/org/apache/poi/ss/formula/functions/EOMonth.java
new file mode 100644
index 000000000..8832e20e7
--- /dev/null
+++ b/src/java/org/apache/poi/ss/formula/functions/EOMonth.java
@@ -0,0 +1,81 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
+package org.apache.poi.ss.formula.functions;
+
+import java.util.Calendar;
+import java.util.Date;
+import java.util.GregorianCalendar;
+
+import org.apache.poi.ss.formula.OperationEvaluationContext;
+import org.apache.poi.ss.formula.eval.ErrorEval;
+import org.apache.poi.ss.formula.eval.EvaluationException;
+import org.apache.poi.ss.formula.eval.NumberEval;
+import org.apache.poi.ss.formula.eval.ValueEval;
+import org.apache.poi.ss.usermodel.DateUtil;
+
+/**
+ * Implementation for the Excel EOMONTH() function.<p/>
+ * <p/>
+ * EOMONTH() returns the date of the last day of a month..<p/>
+ * <p/>
+ * <b>Syntax</b>:<br/>
+ * <b>EOMONTH</b>(<b>start_date</b>,<b>months</b>)<p/>
+ * <p/>
+ * <b>start_date</b> is the starting date of the calculation
+ * <b>months</b> is the number of months to be added to <b>start_date</b>,
+ * to give a new date. For this new date, <b>EOMONTH</b> returns the date of
+ * the last day of the month. <b>months</b> may be positive (in the future),
+ * zero or negative (in the past).
+ */
+public class EOMonth implements FreeRefFunction {
+
+    public static final FreeRefFunction instance = new EOMonth();
+
+    @Override
+    public ValueEval evaluate(ValueEval[] args, OperationEvaluationContext ec) {
+        if (args.length != 2) {
+            return ErrorEval.VALUE_INVALID;
+        }
+
+        try {
+            double startDateAsNumber = NumericFunction.singleOperandEvaluate(args[0], ec.getRowIndex(), ec.getColumnIndex());
+            int months = (int) NumericFunction.singleOperandEvaluate(args[1], ec.getRowIndex(), ec.getColumnIndex());
+
+            // Excel treats date 0 as 1900-01-00; EOMONTH results in 1900-01-31
+            if (startDateAsNumber >= 0.0 && startDateAsNumber < 1.0) {
+                startDateAsNumber = 1.0;
+            }
+
+            Date startDate = DateUtil.getJavaDate(startDateAsNumber, false);
+
+            Calendar cal = new GregorianCalendar();
+            cal.setTime(startDate);
+            cal.set(cal.get(Calendar.YEAR), cal.get(Calendar.MONTH), cal.get(Calendar.DAY_OF_MONTH), 0, 0, 0);
+            cal.set(Calendar.MILLISECOND, 0);
+
+            cal.add(Calendar.MONTH, months + 1);
+            cal.set(Calendar.DAY_OF_MONTH, 1);
+            cal.add(Calendar.DAY_OF_MONTH, -1);
+
+            return new NumberEval(DateUtil.getExcelDate(cal.getTime()));
+        } catch (EvaluationException e) {
+            return e.getErrorEval();
+        }
+    }
+
+}
diff --git a/src/testcases/org/apache/poi/ss/formula/functions/RefValueImplementation.java b/src/testcases/org/apache/poi/ss/formula/functions/RefValueImplementation.java
new file mode 100644
index 000000000..1a3fc1e62
--- /dev/null
+++ b/src/testcases/org/apache/poi/ss/formula/functions/RefValueImplementation.java
@@ -0,0 +1,68 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
+package org.apache.poi.ss.formula.functions;
+
+import org.apache.poi.ss.formula.eval.AreaEval;
+import org.apache.poi.ss.formula.eval.RefEval;
+import org.apache.poi.ss.formula.eval.ValueEval;
+
+final class RefEvalImplementation implements RefEval {
+
+    private final ValueEval value;
+
+    public RefEvalImplementation(ValueEval value) {
+        this.value = value;
+    }
+
+    @Override
+    public AreaEval offset(int relFirstRowIx, int relLastRowIx,
+            int relFirstColIx, int relLastColIx) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public ValueEval getInnerValueEval(int sheetIndex) {
+        return value;
+    }
+
+    @Override
+    public int getNumberOfSheets() {
+        return 1;
+    }
+
+    @Override
+    public int getFirstSheetIndex() {
+        return 0;
+    }
+
+    @Override
+    public int getLastSheetIndex() {
+        return 0;
+    }
+
+    @Override
+    public int getRow() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int getColumn() {
+        throw new UnsupportedOperationException();
+    }
+
+}
diff --git a/src/testcases/org/apache/poi/ss/formula/functions/TestEDate.java b/src/testcases/org/apache/poi/ss/formula/functions/TestEDate.java
index 3a5d527b7..3917f44cb 100644
--- a/src/testcases/org/apache/poi/ss/formula/functions/TestEDate.java
+++ b/src/testcases/org/apache/poi/ss/formula/functions/TestEDate.java
@@ -31,42 +31,7 @@ import org.apache.poi.ss.formula.eval.ValueEval;
 import org.apache.poi.ss.usermodel.DateUtil;
 import org.apache.poi.ss.usermodel.ErrorConstants;
 
-public class TestEDate extends TestCase{
-
-    private final class RefEvalImplementation implements RefEval {
-        private final ValueEval value;
-        
-        public RefEvalImplementation(ValueEval value) {
-            super();
-            this.value = value;
-        }
-
-        public AreaEval offset(int relFirstRowIx, int relLastRowIx,
-                int relFirstColIx, int relLastColIx) {
-            throw new UnsupportedOperationException();
-        }
-
-        public ValueEval getInnerValueEval(int sheetIndex) {
-            return value;
-        }
-        
-        public int getNumberOfSheets() {
-            return 1;
-        }
-        public int getFirstSheetIndex() {
-            return 0;
-        }
-        public int getLastSheetIndex() {
-            return 0;
-        }        
-        
-        public int getRow() {
-            throw new UnsupportedOperationException();
-        }
-        public int getColumn() {
-            throw new UnsupportedOperationException();
-        }
-    }
+public class TestEDate extends TestCase {
 
     public void testEDateProperValues() {
         // verify some border-case combinations of startDate and month-increase
diff --git a/src/testcases/org/apache/poi/ss/formula/functions/TestEOMonth.java b/src/testcases/org/apache/poi/ss/formula/functions/TestEOMonth.java
new file mode 100644
index 000000000..55372b03a
--- /dev/null
+++ b/src/testcases/org/apache/poi/ss/formula/functions/TestEOMonth.java
@@ -0,0 +1,136 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
+package org.apache.poi.ss.formula.functions;
+
+import java.util.Calendar;
+import java.util.Date;
+
+import junit.framework.TestCase;
+import org.apache.poi.ss.formula.OperationEvaluationContext;
+
+import org.apache.poi.ss.formula.eval.BlankEval;
+import org.apache.poi.ss.formula.eval.ErrorEval;
+import org.apache.poi.ss.formula.eval.NumberEval;
+import org.apache.poi.ss.formula.eval.StringEval;
+import org.apache.poi.ss.formula.eval.ValueEval;
+import org.apache.poi.ss.usermodel.DateUtil;
+import org.apache.poi.ss.usermodel.ErrorConstants;
+
+public class TestEOMonth extends TestCase{
+
+    private static final double BAD_DATE = -1.0;
+
+    private static final double DATE_1900_01_01 = 1.0;
+    private static final double DATE_1900_01_31 = 31.0;
+    private static final double DATE_1900_02_28 = 59.0;
+    private static final double DATE_1902_09_26 = 1000.0;
+    private static final double DATE_1902_09_30 = 1004.0;
+    private static final double DATE_2034_06_09 = 49104.0;
+    private static final double DATE_2034_06_30 = 49125.0;
+    private static final double DATE_2034_07_31 = 49156.0;
+
+    private final FreeRefFunction eOMonth = EOMonth.instance;
+    private final OperationEvaluationContext ec = new OperationEvaluationContext(null, null, 0, 0, 0, null);
+
+    public void testEOMonthProperValues() {
+        // verify some border-case combinations of startDate and month-increase
+        checkValue(DATE_1900_01_01, 0, DATE_1900_01_31);
+        checkValue(DATE_1900_01_01, 1, DATE_1900_02_28);
+        checkValue(DATE_1902_09_26, 0, DATE_1902_09_30);
+        checkValue(DATE_2034_06_09, 0, DATE_2034_06_30);
+        checkValue(DATE_2034_06_09, 1, DATE_2034_07_31);
+    }
+
+    public void testEOMonthBadDateValues() {
+        checkValue(0.0, -2, BAD_DATE);
+        checkValue(0.0, -3, BAD_DATE);
+        checkValue(DATE_1900_01_31, -1, BAD_DATE);
+    }
+
+    private void checkValue(double startDate, int monthInc, double expectedResult) {
+        NumberEval result = (NumberEval) eOMonth.evaluate(new ValueEval[] {new NumberEval(startDate), new NumberEval(monthInc)}, ec);
+        assertEquals(expectedResult, result.getNumberValue());
+    }
+
+    public void testEOMonthZeroDate() {
+        NumberEval result = (NumberEval) eOMonth.evaluate(new ValueEval[] {new NumberEval(0), new NumberEval(0)}, ec);
+        assertEquals("0 startDate is 1900-01-00", DATE_1900_01_31, result.getNumberValue());
+
+        result = (NumberEval) eOMonth.evaluate(new ValueEval[] {new NumberEval(0), new NumberEval(1)}, ec);
+        assertEquals("0 startDate is 1900-01-00", DATE_1900_02_28, result.getNumberValue());
+    }
+
+    public void testEOMonthInvalidArguments() {
+        ValueEval result = eOMonth.evaluate(new ValueEval[] {new NumberEval(DATE_1902_09_26)}, ec);
+        assertTrue(result instanceof ErrorEval);
+        assertEquals(ErrorConstants.ERROR_VALUE, ((ErrorEval) result).getErrorCode());
+
+        result = eOMonth.evaluate(new ValueEval[] {new StringEval("a"), new StringEval("b")}, ec);
+        assertTrue(result instanceof ErrorEval);
+        assertEquals(ErrorConstants.ERROR_VALUE, ((ErrorEval) result).getErrorCode());
+    }
+
+    public void testEOMonthIncrease() {
+        checkOffset(new Date(), 2);
+    }
+
+    public void testEOMonthDecrease() {
+        checkOffset(new Date(), -2);
+    }
+
+    private void checkOffset(Date startDate, int offset) {
+        NumberEval result = (NumberEval) eOMonth.evaluate(new ValueEval[] {new NumberEval(DateUtil.getExcelDate(startDate)), new NumberEval(offset)}, ec);
+        Date resultDate = DateUtil.getJavaDate(result.getNumberValue());
+        Calendar instance = Calendar.getInstance();
+        instance.setTime(startDate);
+        instance.add(Calendar.MONTH, offset);
+        instance.add(Calendar.MONTH, 1);
+        instance.set(Calendar.DAY_OF_MONTH, 1);
+        instance.add(Calendar.DAY_OF_MONTH, -1);
+        instance.set(Calendar.HOUR_OF_DAY, 0);
+        instance.set(Calendar.MINUTE, 0);
+        instance.set(Calendar.SECOND, 0);
+        instance.set(Calendar.MILLISECOND, 0);
+        assertEquals(instance.getTime(), resultDate);
+    }
+
+    public void testBug56688() {
+        NumberEval result = (NumberEval) eOMonth.evaluate(new ValueEval[] {new NumberEval(DATE_1902_09_26), new RefEvalImplementation(new NumberEval(0))}, ec);
+        assertEquals(DATE_1902_09_30, result.getNumberValue());
+    }
+
+    public void testRefEvalStartDate() {
+        NumberEval result = (NumberEval) eOMonth.evaluate(new ValueEval[] {new RefEvalImplementation(new NumberEval(DATE_1902_09_26)), new NumberEval(0)}, ec);
+        assertEquals(DATE_1902_09_30, result.getNumberValue());
+    }
+
+    public void testEOMonthBlankValueEval() {
+        NumberEval evaluate = (NumberEval) eOMonth.evaluate(new ValueEval[] {BlankEval.instance, new NumberEval(0)}, ec);
+        assertEquals("Blank is handled as 0", DATE_1900_01_31, evaluate.getNumberValue());
+    }
+
+    public void testEOMonthBlankRefValueEval() {
+        NumberEval result = (NumberEval) eOMonth.evaluate(new ValueEval[] {new RefEvalImplementation(BlankEval.instance), new NumberEval(1)}, ec);
+        assertEquals("Blank is handled as 0",
+                DATE_1900_02_28, result.getNumberValue());
+
+        result = (NumberEval) eOMonth.evaluate(new ValueEval[] {new NumberEval(1), new RefEvalImplementation(BlankEval.instance)}, ec);
+        assertEquals("Blank is handled as 0",
+                DATE_1900_01_31, result.getNumberValue());
+    }
+}