The prognostic significance of extragonadal rather than gonadal presentation of germ-cell tumour in 51 patients presenting between 1979 and 1988 with abdominal tumours was compared with that of 51 control patients with testicular primary tumours matched for bulk fo disease, serum tumour marker concentration, age and year of treatment. Very large volume tumour was found at initial staging in 24 extra-gonadal cases (47%) and high tumour markers in 29 (57%). Actuarial survival at 2 and 5 years was 82% and 70% for cases and 78% and 63%, respectively, for controls. These outcomes were not significantly different and the relative hazard of death for cases compared with controls was 0.7 (95% confidence intervals 0.3-1.5). Thus the presentation of germ-cell tumours with a retroperitoneal mass does not itself adversely influence prognosis compared with testicular presentation with equivalent disease extent. However it is rare for extragonadal presentation to be associated with small volume disease.