A heat exchanger includes an inlet header, an outlet header and a plurality of flat, multi-channel heat exchange tubes extending therebetween. A longitudinally extending member divides the interior of the header into a first chamber on one side thereof for receiving a fluid and a second chamber on the other side thereof. A plurality of multi-channel heat exchange tubes extend between the headers with the respective inlet end of each heat exchange tube passing into the second chamber of the inlet header. Fluid passes through a series of longitudinally spaced openings in the longitudinally extending member for distribution to the inlets to the channels of the multi-channel heat exchange tubes. The fluid may undergo expansion as it passes through the openings.