The management of uterine sarcomas continues to present many difficulties. Primary surgery is the optimal treatment but the role of post-operative radiation remains uncertain. In the mid-1980s, the European Organisation for Research and Treatment of Cancer Gynaecological Cancer Group Study proposed a trial to evaluate adjuvant radiotherapy, as previous non-randomised studies had suggested a survival advantage and improved local control when post-operative radiation was administered. The study opened in 1987 taking 13 years to accrue 224 patients. All uterine sarcoma subtypes were permitted. Patients were required to have undergone as a minimum, TAH and BSO and wahsings (166 patients) but nodal sampling was optional. There were 103 leiomyosarcomas (LMS), 91 carcinosarcomas (CS) and 28 endometrial stromal sarcomas (ESS). Patients were randomised to either observation or pelvic radiation, 51 Gy in 28 fractions over 5 weeks. Hundred and twelve were recruited to each arm. The initial analysis has shown a reduction in local relapse (14 versus 24, p=0.004) but no effect on either OS or PFS. No unexpected toxicity was seen in the radiation arm. No difference in either overall or disease-free survival was demonstrated but there is an increased local control for the CS patients receiving radiation but without any benefit for LMS. Prognostic factor analysis shows that stage, age and histological subtype were important predictors of behaviour which may explain differences between CS and LMS. CS appears to show more kinship to poorly differentiated endometrial carcinomas in behaviour. LMS did not show the same benefit from radiation. These results will help shape future management and clinical trials in uterine sarcomas.