Heat transfer from an array of circular cylinders to an impinging slot jet of water is studied both for single - phase and two - phase conditions. Different geometrical configurations were investigated in order to find those maximising the heat transfer coefficient The dependence on such parameters as jet velocity and subcooling is also examined. For the single - phase situation three different configurations are proposed and correlation for both the cylinder closest to the jet outlet and the other two are given, the latter taking the contribution of free convection into account. For two-phase conditions, one configuration is given, with the same type of correlation for all cases. Increasing the jet subcooling allows higher heat fluxes - up to and exceeding 3 MW/m2 - to be dissipated, but the heat transfer mode worsens.