A review of the use of cis-dichlorodiammineplatinum(II) (cis-platinum) as a single agent in 82 patients with advanced ovarian carcinoma, previously treated with chemotherapy, shows that response rates of 33% and 52% are achieved with doses of 30 and 100 mg/m2 respectively. In 58 previously untreated patients a combination of chlorambucil and cis-platinum (regimen B) was compared in a randomized study with a combination of chlorambucil, cis-platinum, and Adriamycin (regimen C). Complete responses were seen in 32% and 41% of the patients respectively. Remissions were most prolonged in patients with complete regressions, the median being greater than 15 months for both regimens. Because of the good regressions, second-look operations have been possible in 12 patients for the purpose of confirming regression and performing radical surgical removal. In six of these patients, all specimens failed to show evidence of residual carcinoma. The major toxic effects of cis-platinum in our hands are neurologic effects and anemia; both have been reversible after cessation of treatment.