The present phase II trial was undertaken to assess the efficacy and toxicity of a combination of paclitaxel and carboplatin as first-line chemotherapy in patients with metastatic transitional cell carcinoma of the urothelium. Twenty patients (age range 50-79 years; inclusion criteria: WHO performance status 0-2, no previous cytotoxic treatment) with metastatic transitional cell carcinoma of the urothelium were recruited and received cytotoxic treatment with paclitaxel at a dosage of 175 mg m(-2) administered over a 3-h infusion and carboplatin given at an AUC of 5 mg ml(-1) min (according to creatinine clearance) administered every 21 days. A total of 65% of patients achieved remissions (CR+PR), with CR occurring in 40% of patients. A further 15% of patients experienced stable disease. Remissions occurred after 2.4 +/- 0.8 (mean +/- standard deviation; range two to four) treatment cycles. The mean duration of responses (CR+PR) was 8.5 +/- 5.5 months. After a mean observation period of 11.4 +/- 4.8 months, 16 patients (80%) are alive. Toxicity included alopecia of WHO grade 3 in all patients, leucopenia of WHO grades 1 and 2 in ten patients, grade 3 in eight and grade 4 in two patients and, finally, severe thrombocytopenia grade 3 in only three patients. Non-haematological toxicity consisted of polyneuropathy of WHO grade 1 in 13 patients and grade 2 in five patients. We thus conclude that a combination of paclitaxel and carboplatin at the given dosage and schedule constitutes an active, well-tolerated first-line cytotoxic treatment for patients with metastatic urothelial cancer.