A nationwide series of 422 patients with testicular germ cell cancer diagnosed in Finland in 1972-1983 was analysed. The age-adjusted incidence rate, although very low (1.6 per 10(5) male population per year), has increased compared to that in previous decades. The 3-year survival rate has improved markedly and was during the last part of the period high in patients with local (stage I) and regional (stages IIA-B) disease (100% for seminoma and over 90% for non-seminoma patients) but still fairly poor in advanced stages (stages IIC-IV) (58% for seminoma and 26% for non-seminoma patients). The improvement of the survival rate was most marked in non-seminoma patients below the median age (28.5 years). Cisplatin based chemotherapy was one of the major reasons for the improved prognosis, not only in non-seminoma patients but also in those with seminoma. There was no trend with time concerning the stage distribution of the disease. On the basis of relapse rates in stage I non-seminoma and seminoma patients staged surgically and clinically respectively, accuracy of clinical staging but not of surgical staging seemed to have improved. During the early period surgically staged stage I-II non-seminoma patients had a slightly better prognosis than clinical stage I-II patients but a similar difference was not observed during the cisplatin era.