['To identify subgroups of patients with renal stones ≥20 mm that are more suitable for extracorporeal shock wave lithotripsy (ESWL) monotherapy.', 'A total of 376 patients with renal stones ≥20 mm underwent monotherapy with ESWL. The treatment outcome was evaluated after 3 months of follow-up. A stone-free status or fragmentation of stones to 4 mm or smaller was considered efficacious.', 'At 3 months after treatment, the overall stone-free rate was 64.4%, and the efficacy rate was 70.7%. The efficacy rate was 89.4% for patients with a residual stone surface area ≤50% of baseline after the first ESWL, while the efficacy rate was 32.4% for other patients. The efficacy was 92.2% for stones ≤400 mm2 and those with lower radiodensity, as determined by a plain (KUB) film.'] Do treatment of Renal Stones ≥20 mm with Extracorporeal Shock Wave Lithotripsy?