A total of 41 patients with stage 1 malignant teratoma of the testis treated from January 1986 to June 1990 was entered into a pilot study of 2 courses of adjuvant cisplatin-based combination chemotherapy. Of the patients 22 had a high or intermediate risk of relapse according to the Medical Research Council (United Kingdom) prognostic factor analysis and surveillance was instituted for 19 patients with a low relapse risk. The overall relapse rate in this group of patients (median followup 2 years) was 9.7% (5% in the adjuvant group and 16% in the surveillance group), which was significantly better than the 35% rate in the historical series treated by surveillance from 1980 to 1985 and equaled or was possibly better than that reported from adjuvant retroperitoneal lymph node dissection. Justification for consideration of 1 course of adjuvant treatment for such cases is reviewed, and the need for examination of such an approach in a neoadjuvant setting with either lymph node dissection or surveillance is examined.