diff --git a/htdocs/product/fournisseurs.php b/htdocs/product/fournisseurs.php
index 98ab414a8c3..3bf563c82f7 100644
--- a/htdocs/product/fournisseurs.php
+++ b/htdocs/product/fournisseurs.php
@@ -612,7 +612,7 @@ if ($id > 0 || $ref) {
 						$default_vat = $object->tva_tx;
 					}
 				}
-				$vattosuggest = (GETPOST("tva_tx") ?vatrate(GETPOST("tva_tx")) : ($default_vat != '' ?vatrate($default_vat) : ''));
+				$vattosuggest = (GETPOSTISSET("tva_tx") ? vatrate(GETPOST("tva_tx")) : ($default_vat != '' ?vatrate($default_vat) : ''));
 				$vattosuggest = preg_replace('/\s*\(.*\)$/', '', $vattosuggest);
 				print '<input type="text" class="flat" size="5" name="tva_tx" value="'.$vattosuggest.'">';
 				print '</td></tr>';