In this study, exact analytical results are presented for fully developed mixed convective heat transfer of a Newtonian fluid in an open-ended vertical parallel plate microchannel with asymmetric wall heating at uniform heat fluxes. The velocity slip and the temperature jump at the wall are included in the formulation. The effects of the modified mixed convection parameter Gr(q)/Re, the Knudsen number Kn, and the ratio of wall heatflux, r(q) = q(1)/q(2), On the microchannel hydrodynamic and thermal behaviors are determined. Finally, a Nu=f(Gr(q)/Re,Kn,r(q)) expression is developed. For the limiting case of Kn = 0, the results are found to be in an excellent agreement with those in the existing literature.