A new model to predict saturated critical heat flux (CHF) conditions in minichannels and microchannels was developed. The model was compared to 151 experimental data points obtained from CHF studies on mini- and microchannels encompassing various working fluids (Water, R-123, R-113, R-134a, and R-245fa) over a broad range of mass velocities ( 50 – 1600 kg / m 2 s ) and pressures (101–888 kPa). A strong correlation between the model and experimental data was supported by an overall mean absolute error (MAE) of 25.8%. Better predictions were noted ( MAE = 21.3 % ) for experiments carried out using thin wall/substrate minichannel and microchannel configurations as well as those configurations which were not vulnerable to boiling instabilities. The consistent performance and broad applicability of this model demonstrate it as a viable tool for predicting the CHF in minichannels and microchannels.