The prospective study, carried out from February 1992 to January 1996, included 49 patients in clinical Stage I nonseminomatous germ cell testicular tumors (NSGCTT). They were aged 16-40 years (mean, 25 years). Patients were stratified to different risk-adapted therapeutic approaches according to histopathologic findings of primary tumor removed by inguinal orchiectomy. Eleven patients of the 1st group with vascular invasion and majority of embryonal carcinoma components in the primary tumor were treated with adjuvant chemotherapy (2 cycles of BEP). None of them had disease progression after the follow-up of 4-43+ months (mean, 20.9 months) after orchiectomy. Five patients of the 2nd group with vascular invasion and majority of teratoma elements in the primary tumor were treated with primary retroperitoneal lymph node dissection (RPLND). They were followed-up 29-45+ months (mean, 33.4 months) after orchiectomy. Two of them (40%) had pathologic Stage II after RPLND and underwent subsequent BEP chemotherapy. One of them died due to disease progression in disseminated stage 29 months after orchiectomy. The second one lives with no evidence of the disease (NED). Thirty three patients in the 3rd group without vascular invasion were kept under surveillance. They were followed-up 3-48+ months (mean, 22.3 months) after orchiectomy. Disease progression was observed in 5 of them (15.1%), 7-10 months (mean, 8.8 months) following orchiectomy. These patients were treated with BEP chemotherapy and live with NED 1-16+ months (mean, 9.2 months) after completion of the therapy. The overall survival rate in clinical Stage 1 patients was 97.9%. The authors recommend the surveillance policy only in clinical Stage I NSGCTT patients without vascular invasion in the primary tumor.