OBJECTIVE To evaluate potential donor kidneys with asymptomatic calculi detected during screening, and the management of the calculus before, during and after transplantation, as with fewer live donors, marginal kidneys and donors are a significant subgroup in renal transplantation. METHODS Five live-related donors, with one incidentally detected calculus during their routine evaluation, were accepted for transplantation. Of these, three were detected only on spiral computed angiography. There was no biochemical evidence of a metabolic abnormality or history of stone disease. One donor had elective lithotripsy and another nephrolithotomy under ultrasonographic control immediately after perfusion. The others were transplanted with the calculus in situ. Ureteric reimplantation was by the Leadbetter-Politano technique over a JJ stent. RESULTS One recipient patient passed the calculus within 4 h of stent removal. The follow-up ultrasonogram at 3 months showed a stone in only one recipient. In the others, the calculus could not be seen after stent removal. The maximum follow-up was 2 years and graft function has remained normal in all. CONCLUSIONS Voluntary kidney donors with one calculus incidentally detected on routine evaluation form a unique group and can be accepted for transplantation in selected cases. Careful follow-up of the donor and recipient is essential, with early intervention if necessary.