In this study a fragmentation test has been carried out to investigate moisture gain as a function of immersion time for durability test in various aqueous environments such as tap water, sea water, and distilled water at room temperature and 8$0^{circ}C$. The correlation of the variation of moisture gain induced by immersion and drying after immersion in distilled water at 8$0^{circ}C$ with the interfacial shear strength between carbon fiber and epoxy resin has been then investigated. As a result, very similar values of moisture gain were obtained for the various aqueous environments such as sea water, tap water, and distilled water at room temperature. However, at 8$0^{circ}C$, the weight gain was found to be highest for sea water and lowest for distilled water. For specimens weight gain does not mean the moisture gain. We also found that interfacial shear strength of the specimen immersed at 8$0^{circ}C$ decreased with the increase of moisture gain and interfacial shear strength of the specimens immersed for 30,l 60, and 90 days was recovered up to about 60~75% of the initial value by drying for 60 days at room temperature.