Between 1980 and 1984, a total of 171 patients with advanced epithelial ovarian carcinoma and residual tumour after surgery were randomly assigned to treatment groups receiving either cisplatin or thiotepa. The objective of the study was to evaluate the regimes with regard to response and survival. The two groups were well balanced with respect to age, FIGO stage, histology, grade and residual tumour after surgery. In the cisplatin group, 66% responsed to treatment compared to 38% in the thiotepa group (P < 0.00005). The median progression-free survival was 10.5 months and 6.3 months, respectively. The corrected survival was somewhat, but non-significantly, higher in the cisplatin group than in the thiotepa group, with an 8-year corrected survival of 10.6 and 7.4%, respectively. In a multivariate analysis, based on progression-free survival with FIGO stage, residual tumour after surgery, histological type and grade as covariables, treatment with thiotepa had a relative risk of 1.64 compared to cisplatin (95% confidence interval 1.17-2.30, P = 0.004).