diff --git a/lib/Doctrine/DBAL/Types/DateTimeType.php b/lib/Doctrine/DBAL/Types/DateTimeType.php
index ee2475624..1aca8bab2 100644
--- a/lib/Doctrine/DBAL/Types/DateTimeType.php
+++ b/lib/Doctrine/DBAL/Types/DateTimeType.php
@@ -23,11 +23,13 @@ class DateTimeType extends Type
 
     public function convertToDatabaseValue($value, AbstractPlatform $platform)
     {
-        return $value->format($platform->getDateTimeFormatString());
+        return ($value !== null) 
+            ? $value->format($platform->getDateTimeFormatString()) : null;
     }
     
     public function convertToPHPValue($value, AbstractPlatform $platform)
     {
-        return \DateTime::createFromFormat($platform->getDateTimeFormatString(), $value);
+        return ($value !== null) 
+            ? \DateTime::createFromFormat($platform->getDateTimeFormatString(), $value) : null;
     }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/DBAL/Types/DateType.php b/lib/Doctrine/DBAL/Types/DateType.php
index 58cf54b26..29aee72ad 100644
--- a/lib/Doctrine/DBAL/Types/DateType.php
+++ b/lib/Doctrine/DBAL/Types/DateType.php
@@ -23,11 +23,13 @@ class DateType extends Type
 
     public function convertToDatabaseValue($value, AbstractPlatform $platform)
     {
-        return $value->format($platform->getDateFormatString());
+        return ($value !== null) 
+            ? $value->format($platform->getDateFormatString()) : null;
     }
     
     public function convertToPHPValue($value, AbstractPlatform $platform)
     {
-        return \DateTime::createFromFormat($platform->getDateFormatString(), $value);
+        return ($value !== null) 
+            ? \DateTime::createFromFormat($platform->getDateFormatString(), $value) : null;
     }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/DBAL/Types/TimeType.php b/lib/Doctrine/DBAL/Types/TimeType.php
index 8256a5570..e6e1b6882 100644
--- a/lib/Doctrine/DBAL/Types/TimeType.php
+++ b/lib/Doctrine/DBAL/Types/TimeType.php
@@ -31,7 +31,8 @@ class TimeType extends Type
      */
     public function convertToDatabaseValue($value, AbstractPlatform $platform)
     {
-        return $value->format($platform->getTimeFormatString());
+        return ($value !== null) 
+            ? $value->format($platform->getTimeFormatString()) : null;
     }
     
     /**
@@ -41,6 +42,7 @@ class TimeType extends Type
      */
     public function convertToPHPValue($value, AbstractPlatform $platform)
     {
-        return \DateTime::createFromFormat($platform->getTimeFormatString(), $value);
+        return ($value !== null) 
+            ? \DateTime::createFromFormat($platform->getTimeFormatString(), $value) : null;
     }
 }
\ No newline at end of file