The National Cancer Institute of Canada Clinical Trials Group has used carboplatin in two studies in women with ovarian carcinoma. In a phase II study, carboplatin produced a clinical response rate of 28% among patients with tumor persistence or recurrence following one prior cisplatin-containing regimen. Carboplatin was most efficacious in those with smaller tumors, in those who had the best responses to prior cisplatin therapy, and in those with longer intervals between the primary cisplatin treatment and the secondary carboplatin course. In this setting, a starting dose of 320 mg/m2 is suggested. A phase III randomized trial of first-line therapy compared the efficacy of cyclophosphamide/cisplatin with cyclophosphamide/carboplatin. Four hundred eighteen eligible patients were enrolled. The regimens demonstrated comparable efficacy; however, the carboplatin-based regimen was more easily administered and caused less symptomatic toxicity. The long-term results in this population with macroscopic residual disease remain disappointing.