The invention concerns a cooling system for electronic devices, especially computers, comprising an evaporator (1), a vapor-distribution and condensate-collection element (3) and a condenser (2) with a plurality of condenser pipes (6) and a block of fins (5) connecting the condenser pipes (6), wherein the condenser pipes (6) are arranged parallel to each other and extend upwards from the vapor-distribution and condensate-collection element (3) and are closed at their upper ends.