diff --git a/htdocs/webservices/server_thirdparty.php b/htdocs/webservices/server_thirdparty.php
index 542e2980c45..50b8e80e363 100644
--- a/htdocs/webservices/server_thirdparty.php
+++ b/htdocs/webservices/server_thirdparty.php
@@ -685,9 +685,9 @@ function getListOfThirdParties($authentication,$filterthirdparty)
         foreach($filterthirdparty as $key => $val)
         {
             if ($key == 'name'     && $val != '')  $sql.=" AND s.name LIKE '%".$db->escape($val)."%'";
-        	if ($key == 'client'   && $val != '')  $sql.=" AND s.client = ".$db->escape($val);
-            if ($key == 'supplier' && $val != '')  $sql.=" AND s.fournisseur = ".$db->escape($val);
-            if ($key == 'category' && $val != '')  $sql.=" AND s.rowid IN (SELECT fk_soc FROM ".MAIN_DB_PREFIX."categorie_societe WHERE fk_categorie=".$db->escape($val).") ";
+        	if ($key == 'client'   && (int) $val > 0)  $sql.=" AND s.client = ".$db->escape($val);
+            if ($key == 'supplier' && (int) $val > 0)  $sql.=" AND s.fournisseur = ".$db->escape($val);
+            if ($key == 'category' && (int) $val > 0)  $sql.=" AND s.rowid IN (SELECT fk_soc FROM ".MAIN_DB_PREFIX."categorie_societe WHERE fk_categorie=".$db->escape($val).") ";
         }
         dol_syslog("Function: getListOfThirdParties", LOG_DEBUG);