The distribution of intra-abdominal nodal involvement was assessed in 145 patients presenting with testicular tumours referred for staging by computed tomography (CT). Of the 55 patients with definite evidence of nodal enlargement on CT, 33 had tumours of the left testicle, and 22 of the right. Nodal involvement was predominant in the left para-aortic chain in all 33 patients with a left testicular lesion and confined to the left in 31 (93%). Amongst the 22 patients with a right-sided lesion, nodal involvement was predominantly right-sided in 19 (86%) and confined to the right side in 15 (68%). In no patient were the contralateral nodes larger than the ipsilateral nodes. In all 15 patients in this series with early nodal involvement (8 left testicle, 7 right), disease appeared confined to the ipsilateral side. Although crossover of disease does occur, it was only seen in patients with more advanced disease and subsequent to ipsilateral nodal involvement. Knowledge of these findings, which correlate well with data from anatomical, surgical and direct lymphographic studies, should assist in the CT interpretation of equivocal nodal enlargement and aid decisions on the optimal interval for CT follow-up during surveillance.