diff --git a/conn.go b/conn.go
index 901a45c6e..a2fb081e3 100644
--- a/conn.go
+++ b/conn.go
@@ -661,7 +661,7 @@ func (c *Conn) executeQuery(qry *Query) *Iter {
 	case error:
 		return &Iter{err: x}
 	default:
-		return &Iter{err: NewErrProtocol("Unknown type in response to execute query: %s", x)}
+		return &Iter{err: NewErrProtocol("Unknown type in response to execute query (%T): %s", x, x)}
 	}
 }