diff --git a/examples/style/main.cpp b/examples/style/main.cpp
index 75bfccc..1d7e3fe 100644
--- a/examples/style/main.cpp
+++ b/examples/style/main.cpp
@@ -45,6 +45,10 @@ int main()
             sheet->write(row, col, row+col);
     sheet->setColumn(8, 15, 5.0, format4);
 
+    QXlsx::Format *format5 = workbook.addFormat();
+    format5->setNumberFormat(22);
+    sheet->write("A5", QDate(2013, 8, 29), format5);
+
     workbook.save(DATA_PATH"TestStyle.xlsx");
     return 0;
 }
diff --git a/src/xlsxworksheet.cpp b/src/xlsxworksheet.cpp
index 5b69033..54d6bd0 100755
--- a/src/xlsxworksheet.cpp
+++ b/src/xlsxworksheet.cpp
@@ -47,7 +47,8 @@ struct XlsxCellData
         Number,
         Formula,
         ArrayFormula,
-        Boolean
+        Boolean,
+        DateTime
     };
     XlsxCellData(const QVariant &data=QVariant(), CellDataType type=Blank, Format *format=0) :
         value(data), dataType(type), format(format)
@@ -200,7 +201,7 @@ int Worksheet::write(int row, int column, const QVariant &value, Format *format)
     } else if (value.type() == QMetaType::Bool) { //Bool
         ret = writeBool(row,column, value.toBool(), format);
     } else if (value.toDateTime().isValid()) { //DateTime
-
+        ret = writeDateTime(row, column, value.toDateTime(), format);
     } else if (value.toDouble(&ok), ok) { //Number
         if (!m_workbook->isStringsToNumbersEnabled() && value.type() == QMetaType::QString) {
             //Don't convert string to number if the flag not enabled.
@@ -301,6 +302,15 @@ int Worksheet::writeBool(int row, int column, bool value, Format *format)
     return 0;
 }
 
+int Worksheet::writeDateTime(int row, int column, const QDateTime &dt, Format *format)
+{
+    if (checkDimensions(row, column))
+        return -1;
+
+    m_cellTable[row][column] = new XlsxCellData(dt, XlsxCellData::DateTime, format);
+    return 0;
+}
+
 /*
   Check that row and col are valid and store the max and min
   values for use in other methods/elements. The ignore_row /
@@ -499,7 +509,8 @@ void Worksheet::writeCellData(XmlStreamWriter &writer, int row, int col, XlsxCel
         writer.writeAttribute("t", "s");
         writer.writeTextElement("v", cell->value.toString());
     } else if (cell->dataType == XlsxCellData::Number){
-        writer.writeTextElement("v", cell->value.toString());
+        double value = cell->value.toDouble();
+        writer.writeTextElement("v", QString::number(value, 'g', 15));
     } else if (cell->dataType == XlsxCellData::Formula) {
         bool ok = true;
         cell->formula.toDouble(&ok);
@@ -514,6 +525,16 @@ void Worksheet::writeCellData(XmlStreamWriter &writer, int row, int col, XlsxCel
         writer.writeTextElement("v", cell->value.toBool() ? "1" : "0");
     } else if (cell->dataType == XlsxCellData::Blank) {
         //Ok, empty here.
+    } else if (cell->dataType == XlsxCellData::DateTime) {
+        QDateTime epoch(QDate(1899, 12, 31));
+        if (m_workbook->isDate1904())
+            epoch = QDateTime(QDate(1904, 1, 1));
+        qint64 delta = epoch.msecsTo(cell->value.toDateTime());
+        double excel_time = delta / (1000*60*60*24);
+        //Account for Excel erroneously treating 1900 as a leap year.
+        if (!m_workbook->isDate1904() && excel_time > 59)
+            excel_time += 1;
+        writer.writeTextElement("v", QString::number(excel_time, 'g', 15));
     }
     writer.writeEndElement(); //c
 }
diff --git a/src/xlsxworksheet.h b/src/xlsxworksheet.h
index c43f935..0820651 100755
--- a/src/xlsxworksheet.h
+++ b/src/xlsxworksheet.h
@@ -30,6 +30,7 @@
 #include <QMap>
 #include <QVariant>
 class QIODevice;
+class QDateTime;
 
 namespace QXlsx {
 class Package;
@@ -52,6 +53,7 @@ public:
     int writeFormula(int row, int column, const QString &formula, Format *format=0, double result=0);
     int writeBlank(int row, int column, Format *format=0);
     int writeBool(int row, int column, bool value, Format *format=0);
+    int writeDateTime(int row, int column, const QDateTime& dt, Format *format=0);
 
     bool setRow(int row, double height, Format* format=0, bool hidden=false);
     bool setColumn(int colFirst, int colLast, double width, Format* format=0, bool hidden=false);