Carcinosarcomas of the female genital tract are highly malignant tumours composed of carcinomatous and sarcomatous elements. In the past, these tumours were frequently treated as sarcomas. However, a number of arguments, including the sensitivity of these tumours to platinum-based chemotherapy, suggest that these tumours behave more like poorly differentiated carcinomas. The European Organization for Research and Treatment of Cancer (EORTC) Gynaecological Cancer Group therefore decided to perform a prospective phase II study in patients with advanced or metastatic carcinosarcoma with an approach such as that used in gynaecological carcinomas. Eligible patients could have primary or recurrent disease, but prior radiotherapy or chemotherapy was not allowed. The treatment plan recommended upfront debulking, followed by chemotherapy with cisplatin, ifosfamide and doxorubicin. Patients who could be debulked to non-measurable disease remained eligible for the study, but the response assessment was restricted to patients who had measurable disease before the start of chemotherapy. A total of 48 patients (39 primary disease, 9 recurrent disease) were registered, 41 of them being eligible. In 9 patients, all macroscopic lesions could be removed, 32 patients were left with residual disease and were assessable for response. The overall response rate was 56%: a complete response (CR) was observed in 11 (34%) patients and partial response (PR) in 7 (22%) patients. No change occurred in 5 patients and progression in 2 patients. In 7 patients, response could not be assessed. Median survival for all of the 41 eligible patients was 26 months. Severe leucopenia and thrombocytopenia were common and necessitated dose reductions or delays in 60% of patients. From a clinical point of view, the most severe non-haematological toxicity was renal dysfunction, and one patient died of this complication in the absence of disease progression. The results of this study are in-line with the hypothesis that carcinosarcomas are chemosensitive, in particular for the currently investigated regimen. The treatment also included upfront cytoreduction when feasible. Considering the observed toxicities, alternative platinum-based regimens with more favourable toxicity profiles should be explored.