30 ovarian cancer patients with a relapse after prior cisplatin combination chemotherapy were treated in a phase II study with cyclophosphamide 100 mg/m2 orally on days 1-7 and carboplatin 300 mg/m2 intravenously on day 8. Treatment was well tolerated. The major side-effect was thrombocytopenia. 28 patients were evaluable for response. The response was 5 CRs (18%), 4 PRs (14%) 15 SDs (53%) and 4 PDs (14%), for an overall response rate of 32%. The overall progression-free survival lasted from 2 to 23 months, median 8 months. Overall survival ranged from 2 to 35+ months, median 12 months. Patients with a therapy-free interval of more than 1 year showed a higher response rate (46%) than patients with a shorter therapy-free interval (20%). It is concluded that platinum containing second-line chemotherapy, after treatment that already contained cisplatin, is only warranted to palliate symptoms.