To investigate the need for the continued encouragement of early diagnosis of germ cell cancer of the testis, in view of the prevailing cure rate of 95%. The study comprised a retrospective review of 453 unselected and previously untreated patients referred to one centre between 1978 and 1984, comparing the delay from first symptoms with the histological diagnosis. With a delay of < 30 days, 20% of patients had overt metastases at presentation and if the delay was > 4 months. 55% had metastases (chi-squared trend = 15.9, P < 0.001); 18% of Stage-1 patients under surveillance with a delay of < 30 days relapsed, compared with 38% of those with a delay of > 4 months. During the period 1978-1983, 16% of patients were seen after a delay of < 60 days, during the period 1984-1988 the proportion was 22% and during 1989-1994, 31% (chi-squared trend = 8.2, P < 0.004). There was a non-significant trend for a more prolonged delay in those aged < 21 years and > 40 years. Thirty-two patients had chemotherapy with the primary tumour in situ; at orchidectomy, 13 of 18 had no viable malignancy and four of five with viable malignancy also had drug-resistant metastases. Fourteen did not undergo orchidectomy; within a median follow-up of 9 years, one developed a second (histologically different) tumour after 12 years. The outcome of preliminary attempts to use neoadjuvant chemotherapy with or without partial orchidectomy for patients with tumours in a solitary testis is discussed. These findings clearly justify the continued encouragement of early diagnosis, possibly best performed as part of an extended educational programme of genital health at puberty. The long-term potential for testis conservation should be explored initially in tumours in a solitary testis.