Long-term outcome was reviewed in 266 consecutive patients with metastatic non-seminomatous germ cell tumours treated at a single institution. The overall 3 year survival was 77%, and 3 year progression-free survival was 71%. Multivariate analysis identified the following clinical features as independent prognostic factors: the presence of liver, bone or brain metastasis, serum human chorionic gonadotropin > or = 10000 U l-1 and/or alpha-fetoprotein > or = 1000 ng ml-1, a mediastinal mass > 5 cm and the presence of 20 or more lung metastases. Age was not of prognostic significance. Patients without any of the above poor-risk factors had a 3 year survival of 91% regardless of etoposide- or vinblastine-containing chemotherapy compared with 61% for the remaining patients. However, etoposide-containing protocols led to significantly improved survival in patients with at least one poor risk factor. After 612 patient-years of observation no case of secondary leukaemia was observed among 119 surviving patients who had received etoposide as part of their treatment. With a median follow-up of 93 months, five patients developed a second germ cell tumour, two patients nongerm cell malignancies. Fourteen patients relapsed after a disease-free interval of more than 2 years, and nine patients died more than 5 years after commencement of treatment underscoring the need to report long-term results. There is some evidence that cumulative experience translates into improved survival and cure rates for patients with poor-risk metastatic disease.