Abstract: Objective To analyze retrospectively radiotherapy efficacy in Epidemic Kaposi Sarcoma(EKS)in patients associated with acquired immunodeficiency syndromes(AIDS).Methods Total 659 patients with AIDS-related EKS were treated using radiation therapy at the Department of Radiation Oncology of Mondor University Hospital between July 1987 and June 1997, the median follow-up period was 3.2 years.Of which, 398 patients(60.3%)had previously received treatment, either single or combined with interferon, vinblastine, doxorubicin, bleomycin, and/or antiviral treatment.The irradiation was delivered by an accelerator of 4 MeV-X ray or 8 MeV electron beam for extended cutaneous fields, or by 45-100 kV x-ray for very localized fields(oral cavity).The dose delivered was usually 20 Gy in 2 weeks(2.5 Gy/fraction, 4 fractions/week)followed by 2 weeks rest and then second serie of 10 Gy added within 1 week.For oral cavity lesions, a series of dose 15.2Gy was delivered(1.9 Gy/fraction, 4 F per week), of these, 3 patients followed by a 2-3 week rest and then received a similar second serie of 15.2 Gy.Results 629 patients were statistically evaluable and the Objective response rate was 92%, with a complete regression of clinical symptoms for all irradiated patients.The skin and mucosa tolerance was good.There was an obvious correlation between tumor recurrence rate、survival of the patients and the occurrence of opportunistic infections.Conclusion Radiation therapy is an efficient method in the management of epidemic Kaposi sarcoma with AIDS, and good quality of life and improvement of symptoms were achieved after radiotherapy.Meanwhile, proper care and restriction on irradiation dosage and technique used should be advocated in advanced EKS patients associated with AIDS.