Previous studies have reported oxidative degradation of conventional polyethylene (PE) components during shelf aging, following radiation. However, no studies have yet reported data concerning the effect of real-time shelf aging in the manufacturer's packaging on the oxidative degradation of commercially available highly cross-linking PE components. The null hypothesis tested was that in either highly cross-linked or conventional PE acetabular components there would be no significant difference in the amount of oxidative degradation between time zero PE liners and PE liners that had been real-time shelf aged for 2 years in their respective packaging. The results of the study indicated that after 2 years of real-time shelf aging, negligible oxidative degradation occurred with minimal changes in oxidation index, density, and percent crystallinity in commercially available highly cross-linked and conventional PE acetabular liners. These data suggested that oxidative degradation was not a clinical issue in the highly cross-linked and conventional PE components examined after 2 years of real-time shelf aging. It is likely that current manufacturing and packaging technologies have limited the previous clinical concerns related to oxidative degradation during shelf aging of highly cross-linked and conventional PE components.