We investigated two phase heat transfer in staggered and inline micro pin fin arrays, using deionized water and HFE-7200 as working fluids with exit qualities up to 90%. The inline and staggered arrays were wire EDM fabricated to have equivalent pin fin width of 153 mu m and height of 305 mu m on a heated base area of 0.96 cm width by 2.88 cm length. Mass fluxes ranged from 200 to 600 kg/m(2) s for HFE-7200 and 400 to 1300 kg/m(2) s for water. Base heat fluxes ranged from 27 to 118 W/cm(2) for water, and 1 to 36 W/cm(2) for HFE-7200. Average heat transfer coefficient and pressure drop data were obtained and successfully correlated to 3% MAE for water heat transfer coefficient, 10-13% MAE for HFE-7200 heat transfer coefficient, and 15-30% MAE for pressure drop in these pin fin arrays. (c) 2014 Elsevier Ltd. All rights reserved.