Fifty-seven patients who had progressed during or relapsed after randomized first-line combination chemotherapy containing cisplatin or carboplatin were entered into a crossover study in which the analog not previously assigned was administered alone as salvage treatment. Carboplatin and cisplatin were administered at doses of 400 and 100 mg/m2, respectively, every 28 days. Among the 24 patients enrolled in the cisplatin arm, 6 (25%) objective responses (ORs) (3 complete, 3 partial) were observed, whereas 3 partial responses were obtained in the 33 carboplatin-treated patient (9%). Analysis of results, according to response to first-line chemotherapy, demonstrated that the patients who progressed were sensitive only to cisplatin second-line treatment (OR: 3/12), with no responders among carboplatin-treated patients (OR: 0/11). All patients were treated on an outpatient basis and therapy-related toxic effects were mild, consisting chiefly of myelosuppression, and more frequent in the carboplatin group. In our opinion, carboplatin 400 mg/m2 per cycle is scarcely effective in patients with refractory or relapsed ovarian cancer pretreated with cisplatin regimens, whereas cisplatin 100 mg/m2 per cycle appears to be an effective salvage therapy even in patients not responding to carboplatin. The dose of carboplatin should be further escalated especially in refractory patients.