The invention relates to a heat exchanger, especially a charge air cooler (5) for motor vehicles. Said heat exchanger comprises a heat exchange block which is constituted of flat tubes (6) having flat tube ends and ribs (7) and tube bottoms (8) having ventilation passages (9) in which the flat tube ends are received and welded together. The heat exchanger also comprises collecting tanks that can be placed on the tube bottoms (8) and means for deflecting the flow in the feed section of the flat tube ends. The inventive heat exchanger is characterized in that the means for deflecting flow (deflection means 2) and means for reinforcing the flat tube ends (reinforcing means) are configured as an integrated structural component (1).