The effects of γ -irradiation on ultra high molecular weight polyethylene(UHMWPE) used in orthopedic implants was investigated. UHMWPE sheet was recrystallized with different cooling conditions for the purpose of enhancing crosslinking extent of the polymer after r -irradiation. Creep and wear behavior of UHMWPE which was prepared by slow cooling and rapidly quenching were investigated. It was found that UHMWPE sheet recrystallized under slow cooling condition has a lower creep rate than UHMWPE sheet recrystallized under rapidly quenching condition. The linear wear rate of UHMWPE recrystallized under rapidly quenching condition was lower than that of UHMWPE sheet recrystallized under slow cooling condition.