Nerve sparing retroperitoneal lymph node dissection reliably preserves emission and ejaculation in patients with clinical stage I nonseminoma. The fertility of 51 patients who underwent nerve sparing retroperitoneal lymph node dissection was assessed by 3 different methods: standard semen analysis, analysis of chromatin content by deoxyribonucleic acid histogram and assessment of ultimate fertility status by a questionnaire. Approximately 75% of these patients have semen analyses generally considered to be in the normal range. Virtually all patients who underwent deoxyribonucleic acid histogram analysis had histograms similar to controls. A retrospective analysis of fertility was performed in 201 patients who had previously undergone nerve sparing retroperitoneal lymph node dissection. Of these patients who attempted pregnancy after nerve sparing retroperitoneal lymph node dissection 76% have been successful. Approximately 75% of patients who present with clinical stage I nonseminoma are potentially fertile. Nerve sparing retroperitoneal lymph node dissection is capable of preserving this potential in allowing these patients to father children.