Probabilistic two-phase flow map pressure drop and void fraction models are developed for 6-port microchannels in order to provide a more accurate and common means of predicting void fraction and pressure drop. The models are developed for R134a, R410A, and air-water in 6-port microchannels at 10 degrees C saturation temperatures, qualities from 0 to 1, and mass fluxes varying from 50 to 300 kg/m(2) s. The probabilistic flow map models developed are found to accurately predict void fraction and pressure drop for the entire quality range and for all three fluids. (c) 2006 Elsevier Ltd. All rights reserved.