diff --git a/src/Spout/Writer/XLSX/Manager/WorksheetManager.php b/src/Spout/Writer/XLSX/Manager/WorksheetManager.php
index 741d0aa..0877da5 100644
--- a/src/Spout/Writer/XLSX/Manager/WorksheetManager.php
+++ b/src/Spout/Writer/XLSX/Manager/WorksheetManager.php
@@ -214,6 +214,8 @@ EOD;
 
         if ($cell->isString()) {
             $cellXML .= $this->getCellXMLFragmentForNonEmptyString($cell->getValue());
+        } elseif ($cell->isDate()) {
+            $cellXML .= ' t="d"><v>' . ($cell->getValue()->format(\DateTime::ATOM)) . '</v></c>';
         } elseif ($cell->isBoolean()) {
             $cellXML .= ' t="b"><v>' . (int) ($cell->getValue()) . '</v></c>';
         } elseif ($cell->isNumeric()) {