This study concerns water saturated flow boiling heat transfer in an array of staggered square micro-pin-fins having a 200 x 200 mu m(2) cross-section by a 670 mu m height. Three inlet temperatures of 90, 60, and 30 degrees C, six mass velocities for each inlet temperature, ranging from 183 to 420 kg/m(2) s, and outlet pressures between 1.03 and 1.08 bar were tested. Heat fluxes ranged from 23.7 to 248.5 W/cm(2). Heat transfer coefficient was fairly constant at high quality, insensitive to both quality and mass velocity. Heat transfer was enhanced by inlet subcooling at low quality. Possible heat transfer mechanism was discussed. (C) 2008 Elsevier Ltd. All rights reserved.