Polyvinyl ester green composites were synthesized with walnut shell powder (WSP) by in-situ polymerization technique. The green composites have been evaluated for mechanical properties such as tensile strength, tensile modulus and hardness. Sliding wear loss, specific wear rate and coefficient of friction were investigated by using computerized pin-on–disc machine at normal applied loads of 20, 30 and 40N; at a sliding velocity of 1.5 m/s and at two abrading distances viz., 100 and 200 m. The results indicate that the wear volume loss increases with increasing abrading distance/load. It was found that WSP filled vinyl ester composites exhibit lower wear rate and higher coefficient of friction as compared to vinyl ester green composites. Further, the worn surfaces were examined by scanning electron microscopy (SEM), to give insight in to the wear mechanism, while their mechanical properties were investigated using tensile strength, tensile modulus and hardness test machines.