A heat exchanger, in particular for a heating or air-conditioning system in a motor vehicle, having an evaporator unit to which a refrigerant medium can be supplied via a distribution unit and through which said refrigerant medium flows and around which said refrigerant medium flows after only one diversion (two-block design) at the bottom in a diversion unit, wherein the distribution unit is designed to effect a uniform distribution of the refrigerant medium over the full width of the evaporator.
