diff --git a/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFCell.java b/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFCell.java
index 6bbcf1a8c..314303743 100644
--- a/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFCell.java
+++ b/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFCell.java
@@ -359,9 +359,9 @@ public final class XSSFCell implements Cell {
      */
     public void setCellFormula(String formula) {
         XSSFWorkbook wb = row.getSheet().getWorkbook();
-        if (formula == null && cell.isSetF()) {
+        if (formula == null) {
             wb.onDeleteFormula(this);
-            cell.unsetF();
+            if(cell.isSetF()) cell.unsetF();
             return;
         }
 
diff --git a/src/testcases/org/apache/poi/ss/usermodel/BaseTestCell.java b/src/testcases/org/apache/poi/ss/usermodel/BaseTestCell.java
index 1a987c1ac..4e747b289 100755
--- a/src/testcases/org/apache/poi/ss/usermodel/BaseTestCell.java
+++ b/src/testcases/org/apache/poi/ss/usermodel/BaseTestCell.java
@@ -265,7 +265,13 @@ public abstract class BaseTestCell extends TestCase {
 		assertEquals("I changed!", c2.getStringCellValue());
 		assertEquals(Cell.CELL_TYPE_FORMULA, c2.getCellType());
 		assertEquals(Cell.CELL_TYPE_STRING, c2.getCachedFormulaResultType());
-	}
+
+        //calglin Cell.setCellFormula(null) for a non-formula cell
+        Cell c3 = r.createCell(2);
+        c3.setCellFormula(null);
+        assertEquals(Cell.CELL_TYPE_BLANK, c3.getCellType());
+
+    }
 	private Cell createACell() {
 		return _testDataProvider.createWorkbook().createSheet("Sheet1").createRow(0).createCell(0);
 	}