Numerical results of the Navier-Stokes equations and the DSMC method for H-2/N-2 and H-2/N-2/CO2 mixtures in planar microchannels are compared in order to verify the accuracy of slip/jump boundary conditions in multicomponent flows. For the solution of the Navier-Stokes and energy equations, a finite-volume method is used together with a complete set of slip/jump boundary conditions derived from the kinetic theory of gases. In order to compare the accuracy of these two methods, different wall temperatures as well as inlet mass flow rates are examined. Isothermal flow is also considered for comparison with available analytical solutions for slip flows. The Knudsen number typically ranged between 0.015 < Kn < 0.09 with a Reynolds number of 5 < Re < 15. The two methods are generally in good agreement under the conditions studied especially at low to moderate Knudsen numbers. (C), 2012 Elsevier Ltd. All rights reserved.