OBJECTIVE To evaluate the resection of the retroperitoneal residual tumour mass (RRTM) for histological examination after chemotherapy in patients with disseminated non-seminomatous testicular germ cell tumours (NSTGCTs), with particular attention to surgical morbidity. METHODS From 1979 to 1995, 112 patients (mean age 28 years, range 16-53) with NSTGCT had residual disease after chemotherapy for which surgical evaluation was indicated; the histology of the residual tumour and the surgical complications were assessed. Possible associations between the occurrence of surgical complications and the age of the patient, size of the residual tumour, operative duration, previous laparotomy and pathological findings were evaluated. RESULTS The median size of the residual tumour was 4 cm (range 0-18); histological examination revealed viable tumour in 9%, mature teratoma in 44% and necrosis/fibrosis in 44% of the patients. In three patients (2.8%) no residual tumour mass was found at laparotomy. There were 26 complications in 20 patients (18%); urinary tract infection was the most common, occurring in nine patients (8%). One patient died during the induction of anaesthesia. There were no significant relationships between the occurrence of complications and age, size of the residual tumour, operative duration, previous laparotomy or pathological findings. CONCLUSIONS The resection of RRTM after polychemotherapy treatment for disseminated NSTGCT is a safe surgical procedure, with low treatment morbidity consisting mainly of urinary tract infection. Knowledge of the potential complications may help to prevent morbidity. However, the surgical evaluation of the ultimate effect of polychemotherapy remains the gold standard.