Sorption of tritiated water on organic materials such as rubber, linoleum and acrylic resin, and subsequent desorption by wet gas purging were studied. Sorption amount was found to increase slightly with contact time. Adsorption coefficient, which was defined as the ratio of adsorption amount to the initial HTO concentration in the exposed gas phase, was compared with reported values on various materials. From the decrease of tritium concentration in the swept gas during desorption by wet gas purging, desorption rate constants were calculated. They were in the order of 10−2 min−1 and were found to decrease with the contact time.