BACKGROUND This study was performed in order to evaluate the immediate and long-term outcome of patients undergoing extracorporeal shock wave lithotripsy (ESWL) for isolated lower pole calculi. METHODS Three hundred and seventy renal units of 350 patients (240 men and 110 women; mean age 55 years) with isolated lower pole renal stones of smaller than 2 cm2 were studied. Follow up ranged from 1 to 52 months (mean, 15 months) to time of censorship, significant period of secondary urologic evaluation. RESULTS Out of 370 renal units in 350 patients, 212 (57, 29%) were stone-free 1 month after ESWL and 21 (5.67%) spontaneously became stone-free within another 1-52 months (mean, 15 months). Intervention was required after 1-52 months (mean, 17.5 months) and accomplished by ESWL alone (30/350 patients 8.57%) or combined with retrograde endoscopy (10/350 patients 2.85%) while retrograde manipulation was necessary in two of the 350 patients (0.57%). CONCLUSIONS Extracorporeal shock wave lithotripsy is the initial treatment of choice in patients with lower pole stones < 2 cm2, because the overall stone-free rate is acceptable and because even in the residual calculi, the risk of suffering symptomatic episodes requiring secondary intervention is low.