A report on the treatment of 165 epithelial tumours of the ovary (60 of which were stage II and 105 were stage III) by medical means after surgery. The results are far better in stage II cases for the length of survival without disease and the 5 year survival rate when surgical excision was complete (40 months and 43%) as compared with the disease-free interval and survival when surgical excision was incomplete (14 months and 27%) (p less than 0.05). There was a significant difference (p less than 0.05) in favour of pelvic and total abdominal irradiation as compared with other added therapeutic measures: 41 months as a median of disease-free interval and 60% survival at 5 years for patients who had pelvic and total abdominal irradiation combined with chemotherapy as against 26 months and 38% survival for patients who had only pelvic irradiation with chemotherapy. In the 105 stage III cases the median interval of disease-free survival and the survival at 5 years are quite different (p less than 0.01) for the 57 cases who had complete surgical excision (30 months and 17.5%) as compared with those who only had incomplete surgical treatment (1.4 months and 2%). There was no significant difference in the disease-free interval and the 5 year survival rate according to the different post-surgical therapeutic measures, whether these were chemotherapy alone or pelvic irradiation or pelvic and abdominal irradiation. These results are compared with those of other treatments following surgery of tumours of the ovary (a historical comparison and random trials).