Forced convection of non-Newtonian nanofluid, aqueous solution of carboxymethyl cellulose (CMC)–Aluminum oxide through a microtube is studied numerically. The length and diameter of tube are mm and mm, respectively which means the length is long enough compared to the diameter. The effects of different values of nanoparticles volume fraction, slip coefficient and Reynolds number are investigated on the slip velocity and temperature jump boundary conditions. Moreover the suitable validations are presented to confirm the achieved results accuracy. The results are shown as the dimensionless velocity and temperature profiles; however the profiles of local and averaged Nusselt number are also provided. It is seen that more volume fraction and slip coefficient correspond to higher Nusselt number especially at larger amounts of Re.