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 28215641f..373b65382 100644
--- a/src/java/org/apache/poi/ss/formula/atp/AnalysisToolPak.java
+++ b/src/java/org/apache/poi/ss/formula/atp/AnalysisToolPak.java
@@ -15,9 +15,7 @@ import org.apache.poi.ss.formula.eval.NotImplementedException;
 import org.apache.poi.ss.formula.eval.ValueEval;
 import org.apache.poi.ss.formula.function.FunctionMetadata;
 import org.apache.poi.ss.formula.function.FunctionMetadataRegistry;
-import org.apache.poi.ss.formula.functions.EDate;
-import org.apache.poi.ss.formula.functions.FreeRefFunction;
-import org.apache.poi.ss.formula.functions.Sumifs;
+import org.apache.poi.ss.formula.functions.*;
 import org.apache.poi.ss.formula.udf.UDFFinder;
 
 import java.util.*;
@@ -74,7 +72,7 @@ public final class AnalysisToolPak implements UDFFinder {
         r(m, "BIN2DEC", null);
         r(m, "BIN2HEX", null);
         r(m, "BIN2OCT", null);
-        r(m, "COMPLEX", null);
+        r(m, "COMPLEX", Complex.instance);
         r(m, "CONVERT", null);
         r(m, "COUNTIFS", null);
         r(m, "COUPDAYBS", null);
diff --git a/src/java/org/apache/poi/ss/formula/functions/Complex.java b/src/java/org/apache/poi/ss/formula/functions/Complex.java
index d37ab70de..0c3981102 100644
--- a/src/java/org/apache/poi/ss/formula/functions/Complex.java
+++ b/src/java/org/apache/poi/ss/formula/functions/Complex.java
@@ -1,5 +1,6 @@
 package org.apache.poi.ss.formula.functions;
 
+import org.apache.poi.ss.formula.OperationEvaluationContext;
 import org.apache.poi.ss.formula.eval.*;
 
 /**
@@ -30,7 +31,9 @@ import org.apache.poi.ss.formula.eval.*;
  *
  * @author cedric dot walter @ gmail dot com
  */
-public class Complex extends Var2or3ArgFunction {
+public class Complex extends Var2or3ArgFunction implements FreeRefFunction {
+
+    public static final FreeRefFunction instance = new Complex();
 
     public static final String DEFAULT_SUFFIX = "i";
     public static final String SUPPORTED_SUFFIX = "j";
@@ -116,4 +119,15 @@ public class Complex extends Var2or3ArgFunction {
         return (number == Math.floor(number)) && !Double.isInfinite(number);
     }
 
+    @Override
+    public ValueEval evaluate(ValueEval[] args, OperationEvaluationContext ec) {
+        if (args.length == 2) {
+            return evaluate(ec.getRowIndex(), ec.getColumnIndex(), args[0], args[1]);
+        }
+        if (args.length == 3) {
+            return evaluate(ec.getRowIndex(), ec.getColumnIndex(), args[0], args[1], args[2]);
+        }
+
+        return ErrorEval.VALUE_INVALID;
+    }
 }
diff --git a/test-data/spreadsheet/ComplexFunctionTestCaseData.xls b/test-data/spreadsheet/ComplexFunctionTestCaseData.xls
new file mode 100644
index 000000000..0d72e7d14
Binary files /dev/null and b/test-data/spreadsheet/ComplexFunctionTestCaseData.xls differ