We report a retrospective review of our experience with close observation after orchiectomy in clinical stage I nonseminomatous germ cell tumors (NSGCT) of the testis during a 10-year period. Twenty-four patients were followed between 1977 and 1986 for a median duration of 47 months (24-112 months). Six of 24 (25%) relapsed at a median of 3.5 months (2-46 months) after orchiectomy; all of these were treated with chemotherapy and are in complete remission at a median of 55 months (27-69 months) after diagnosis of recurrence. Eighteen other (75%) who did not relapse are without evidence of disease at a median of 39 months (24-112 months) after orchiectomy. Orchiectomy alone followed by close observation in clinical stage I NSGCT is a reasonable approach in reliable patient populations at well-equipped centers where adequate follow-up is possible.