diff --git a/components/fpspreadsheet/examples/ooxmldemo/ooxmlwrite.lpr b/components/fpspreadsheet/examples/ooxmldemo/ooxmlwrite.lpr
index 0354d2c16..85ad10d7d 100644
--- a/components/fpspreadsheet/examples/ooxmldemo/ooxmlwrite.lpr
+++ b/components/fpspreadsheet/examples/ooxmldemo/ooxmlwrite.lpr
@@ -87,7 +87,9 @@ begin
   MyWorksheet.WriteUTF8Text(0, 3, 'Fourth');
 
   // Write current date/time
-  MyWorksheet.WriteDateTime(0, 5, now);
+  MyWorksheet.WriteDateTime(0, 5, now, nfShortDate);
+  MyWorksheet.WriteDateTime(1, 5, now, nfShortTime);
+  MyWorksheet.WriteDateTime(2, 5, now, 'nn:ss.zzz');
 
   // Save the spreadsheet to a file
   MyWorkbook.WriteToFile(MyDir + 'test.xlsx', sfOOXML);
diff --git a/components/fpspreadsheet/xlsxooxml.pas b/components/fpspreadsheet/xlsxooxml.pas
index 1358971a9..c6b63a934 100755
--- a/components/fpspreadsheet/xlsxooxml.pas
+++ b/components/fpspreadsheet/xlsxooxml.pas
@@ -115,7 +115,7 @@ type
 implementation
 
 uses
-  variants, fpsNumFormatParser;
+  variants, fpsNumFormatParser, xlscommon;
 
 const
   { OOXML general XML constants }
@@ -1261,8 +1261,12 @@ end;
 *******************************************************************}
 procedure TsSpreadOOXMLWriter.WriteDateTime(AStream: TStream;
   const ARow, ACol: Cardinal; const AValue: TDateTime; ACell: PCell);
+var
+  ExcelDateSerial: double;
 begin
-  WriteLabel(AStream, ARow, ACol, FormatDateTime(ISO8601Format, AValue), ACell);
+  ExcelDateSerial := ConvertDateTimeToExcelDateTime(AValue, dm1900); //FDateMode);
+  WriteNumber(AStream, ARow, ACol, ExcelDateSerial, ACell);
+//  WriteLabel(AStream, ARow, ACol, FormatDateTime(ISO8601Format, AValue), ACell);
 end;
 
 {