diff --git a/psycopg/typecast_basic.c b/psycopg/typecast_basic.c
index 20c7b81f..5e2a93ea 100644
--- a/psycopg/typecast_basic.c
+++ b/psycopg/typecast_basic.c
@@ -65,7 +65,7 @@ typecast_FLOAT_cast(const char *s, Py_ssize_t len, PyObject *curs)
     PyObject *str = NULL, *flo = NULL;
 
     if (s == NULL) {Py_INCREF(Py_None); return Py_None;}
-    str = Text_FromUTF8AndSize(s, len);
+    if (!(str = Text_FromUTF8AndSize(s, len))) { return NULL; }
 #if PY_MAJOR_VERSION < 3
     flo = PyFloat_FromString(str, NULL);
 #else