diff --git a/htdocs/projet/class/project.class.php b/htdocs/projet/class/project.class.php
index d423bc48ae1e85ecf8981373313ae0551fdf0f87..1d24076df27c0e386b6b0a825dc623ede632d404 100644
--- a/htdocs/projet/class/project.class.php
+++ b/htdocs/projet/class/project.class.php
@@ -416,13 +416,13 @@ class Project extends CommonObject
 		{
 			if (empty($datefieldname) && ! empty($this->table_element_date)) $datefieldname=$this->table_element_date;
 			if (empty($datefieldname)) return 'Error this object has no date field defined';
-			$sql.=" AND ".$datefieldname." >= '".$this->db->idate($dates)."'";
+			$sql.=" AND (".$datefieldname." >= '".$this->db->idate($dates)."' OR ".$datefieldname." IS NULL)";
 		}
     	if ($datee > 0)
 		{
 			if (empty($datefieldname) && ! empty($this->table_element_date)) $datefieldname=$this->table_element_date;
 			if (empty($datefieldname)) return 'Error this object has no date field defined';
-			$sql.=" AND ".$datefieldname." <= '".$this->db->idate($datee)."'";
+			$sql.=" AND (".$datefieldname." <= '".$this->db->idate($datee)."' OR ".$datefieldname." IS NULL)";
 		}
 		if (! $sql) return -1;