Abstract: Objective : To investigate the acute radiation injury and the cosmetic results of conservative treatment of breast cancer using various methods of boost irradiation. Methods : Fifty-one patients with early breast cancer treated by conservative surgery plus radiation therapy, from 1990 to 1990, were analyzed retrospectively. The cases were divided into two groups, i.e. 20 cases with brachytherapy boost irradiation (group A) and 31 cases with electron beam boost irradiation (group B).All the patients received external irradiation 46Gy/23F/4.6W with two tangential fields following tumorectomy + axillary lymph node dissection. In group A, Iridium 192 HDR implants was used for tumor bed boost irradiation 14-20Gy/1 -3F. In group B, the boost was given 20Gy/10F/2W by 9-17 Me Velectron beam. The patients were followed-up periodically over 5 years. Results : The 5 -year survival rate was 90.0% in group A and 87.09% in group B (P>0.05). In acute radiation injury, there were 6 cases with local dermatic injury of ≥ 3 grade in group A, the incidence was 30.0%(6/20) and 2 cases in group B, the incidence was 6.5%(2/31) (P<0.05). The cosmetic effect was different between the groups;the rate of excellency for brachytherapy group (group A) was 60.0% (12/20) and 87.1% (27/31) in group B (P<0.05). Conclusion : The 5-year survival rate has no difference between the groups. But the rate of the radiation injury is lower in the group using electron beam boost and the cosmetic result is better than that using Iridium 192 HDR implant.