diff --git a/dibi/drivers/mysqli.php b/dibi/drivers/mysqli.php
index 42f2e56f..1d46742e 100644
--- a/dibi/drivers/mysqli.php
+++ b/dibi/drivers/mysqli.php
@@ -194,7 +194,7 @@ class DibiMySqliDriver extends DibiObject implements IDibiDriver, IDibiResultDri
 	 */
 	public function getAffectedRows()
 	{
-		return mysqli_affected_rows($this->connection);
+		return mysqli_affected_rows($this->connection) === -1 ? FALSE : mysqli_affected_rows($this->connection);
 	}