A compact electrical connector assembly comprises a printed circuit board having a predetermined thickness and defining a first face and a second face opposite to the first face. A low profile electrical connector sits on the first face of the printed circuit board and comprises an insulating housing defining a longitudinal central slot opened forwardly with first contacts and second contacts respectively retained at opposite sides of the central slot. A card is inserted into the central slot at an angle with regard to the printed circuit board, and then rotated from the second face to the first face of the printed circuit board until reaching to a secured position which is substantially overlapped with the printed circuit board.