The effect of viscosity coeffcient on aero-thermal prediction of re-entry flows is studied by computing the flowfield with different formulations for individual species viscosity. Blottner viscosity model and collision integral method are used to calculate the species viscosity. The surface properties of FIRE II re-entry capsule at 35 km altitude computed using the above two viscosity formulations are compared with the in-flight measurements. The stagnation point heating rate predicted by collision integral method is 10 % higher than that given by Blottner model. Afterbody heat transfer rate computed by both formulations are within the scatter of flight data. Shock position predicted by both methods differ slightly at the shoulder region. However their effect on surface pressure is minimal.