In this study we evaluate the interfacial shear strength and scratch resistance of medical grade ultra-high molecular weight polyethylene (UHMWPE) (GUR 1050 resin) as a function of polymer crystallinity. Crystallinity was controlled by heating UHMWPE samples to a temperature above its melting point and varying the hold time and cooling rates. Degree of crystallinity of the samples was evaluated using differential scanning calorimetry (DSC). Quantitative nanoscale friction experiments were conducted using an atomic force microscope with commercially available Si3N4 probes under dry conditions. A higher crystallinity resulted in lower friction force and lower interfacial shear strength as well as increased scratch resistance. The trend in friction response was observed in microscale friction measurements.