This study deals with heat transfer and entropy generation analysis of pressure driven flow of a power law fluid in a microchannel. The microchannel is subject to uniform heat flux boundary condition at the walls. The slip at the walls has been modeled through three different slip laws, namely: non-linear Navier slip law, Hatzikiriakos slip law and asymptotic slip law. All the governing equations have been solved analytically. The effect of various friction coefficients of the slip laws on velocity distribution, temperature distribution, Nusselt number, entropy generation rate and Bejan number has been shown. The reason and the justification behind the trends observed have been discussed in detail. A comparison has been made between Hatzikiriakos slip law and asymptotic slip law with regards to Nusselt number and average entropy generation rate. It is observed that, for the same slip coefficients, the value of Nusselt number as predicted by Hatzikinakos slip law is higher and average entropy generation rate is lower than the corresponding values predicted by asymptotic slip law; and this difference increases with increase in the value of slip coefficients. (C) 2014 Elsevier Ltd. All rights reserved.