diff --git a/ext/zlib/zlib.c b/ext/zlib/zlib.c
index 5a8a634eabc..ed8299e6d05 100644
--- a/ext/zlib/zlib.c
+++ b/ext/zlib/zlib.c
@@ -1032,6 +1032,7 @@ int php_deflate_string(const char *str, uint str_length, char **newstr, uint *ne
 
 	*new_length = buf_used + 10 + 8;
 	*newstr = buffer;
+	deflateEnd(&ZLIBG(stream));
 
 	return SUCCESS;
 }