Recombinant interleukin-2(IL-2) has demonstrated as an antineoplastic agent in mice and human, but the relatively low response rates observed in clinical trials. Therefore, the present study was undertaken in order to evaluate therapeutic activities of IL-2 for the establishment of therapeutic applications. At the onset of the experiment, normal C3H/HeN mice were injected with 5$ imes$10$^$6/ RD-995 tumor cells, murine ultraviolet radiation-induced fibrosarcoma, intraperitoneally. Beginning on day 6, experimental groups were treated with a 5-day course of IL-2(subcutaneous injection of 30,000 IU every 12 hours for 5 days). The result of this experiment revealed that body weight gradually decreased from 20th day in control mice. Subcutaneous IL-2 therapy prevented partially decrease body weight, and prolonged survival of mice compared with control group.