Ten evaluable patients with progressive ovarian adenocarcinoma received third-line chemotherapy consisting of weekly cisplatin (cis-diamminedichloroplatinum[II]) at a dose of 1 mg/kg weekly for a maximum of 6 weeks followed by 60 mg/m2 every 3 weeks. There was no life-threatening toxicity. Seven patients (70%) achieved an objective partial response. This is the highest response rate achieved, to date, by third-line chemotherapy in women with advanced ovarian adenocarcinoma. Weekly cisplatin therefore warrants a trial as first-line therapy.