diff --git a/src/Spout/Writer/ODS/Manager/WorksheetManager.php b/src/Spout/Writer/ODS/Manager/WorksheetManager.php
index 4dfe9c8..0f8a5ae 100644
--- a/src/Spout/Writer/ODS/Manager/WorksheetManager.php
+++ b/src/Spout/Writer/ODS/Manager/WorksheetManager.php
@@ -204,6 +204,22 @@ class WorksheetManager implements WorksheetManagerInterface
$data .= ' office:value-type="float" calcext:value-type="float" office:value="' . $cell->getValue() . '">';
$data .= '' . $cell->getValue() . '';
$data .= '';
+ } elseif ($cell->isDate()) {
+ $value = $cell->getValue();
+ if ($value instanceof \DateTime) {
+ $data .= ' office:value-type="date" calcext:value-type="date" office:date-value="' . $value->format(\DateTimeInterface::W3C) . '">';
+ $data .= '' . $value->format(\DateTimeInterface::W3C) . '';
+ } else if ($value instanceof \DateInterval) {
+ // workaround for missing DateInterval::format('c'), see https://stackoverflow.com/a/61088115/53538
+ static $f = ['M0S', 'H0M', 'DT0H', 'M0D', 'Y0M', 'P0Y', 'Y0M', 'P0M'];
+ static $r = ['M', 'H', 'DT', 'M', 'Y0M', 'P', 'Y', 'P'];
+ $value = rtrim(str_replace($f, $r, $value->format('P%yY%mM%dDT%hH%iM%sS')), 'PT') ?: $default;
+ $data .= ' office:value-type="time" office:time-value="' . $value . '">';
+ $data .= '' . $value . '';
+ } else {
+ throw new InvalidArgumentException('Trying to add a date value with an unsupported type: ' . \gettype($cell->getValue()));
+ }
+ $data .= '';
} elseif ($cell->isError() && is_string($cell->getValueEvenIfError())) {
// only writes the error value if it's a string
$data .= ' office:value-type="string" calcext:value-type="error" office:value="">';