The effect of aging on the properties of paper sized with chitosan, cationic starch, and PVA was investigated under accelerating conditions (90 ºC and 50% RH). The observations from this study demonstrate that the brightness and pH of papers decrease with an increase in aging time. At each aging time, paper sized with chitosan shows the highest reduction in brightness, whereas decreases in brightness in papers sized with PVA and cationic starch do not show much difference. The results demonstrate that paper sized with any of the polymers gave higher levels of tear index, tensile index, and folding endurance than the control sheet. Statistical analysis indicated that the polymers used in this experiment have a statistically significant effect on the folding endurance of sized paper that was highest in the cases of PVA and chitosan.