The long-term effect of gamma irradiation on paper was studied. Three types of paper (pure rag, mixed rag, and mechanically prepared woodpulp) were subjected to three treatments: gamma irradiation, accelerated dry aging, and radiation followed by aging. The effects of these treatments on the physical properties of the paper samples were assessed by measuring alterations in mechanical strength as determined by changes in folding endurance and tear resistance when compared to the untreated control samples. It was found that gamma irradiation caused a decrease in the mechanical strength of the papers similar to that resulting from accelerated dry aging. A synergistic effect was found when both irradiation and accelerated aging were performed on the paper samples, demonstrated by an even greater decrease in both fold endurance and tear resistance than that resulting from either gamma irradiation or accelerated dry aging alone. -- AATA