The effects of capillary grooves on surface wetting and evaporation have been analysed. An attempt has been made to obtain expressions which approximately describe the increase in heat transfer in order to select for given properties and temperature differences a groove of optimum design. For this purpose, it is assumed that the heat transfer mechanism is determined by thermal resistance of the liquid layers inside the grooves. From a numerical evaluation of linearized equations, heat transfer rates have been computed for grooves with triangular, semicircular, and square cross sections.