Urinary lithiasis after renal transplantation is a relatively uncommon disease; the predisposing factors and the composition of calculi are identical to those of patients with native kidneys. We present a case of a 45-year-old woman with a staghorn stone in a left-sided transplanted kidney who was treated successfully by percutaneous nephrolithotomy (PCNL). After reviewing the literature, we conclude that PCNL in transplanted kidney is a feasible and safe procedure. The technical aspects of the procedure, such as patient position and the use of the ultrasound-guided caliceal puncture, are stressed.