We treated 12 patients with sixteen renal and one ureteral cystine stones primarily with extracorporeal shock-wave lithotripsy (ESWL). Among the stones thirteen were >25 mm. In four stones <25 mm, three stones completely disappeared and 1 was reduced to small fragments, following ESWL. In thirteen stones >25 mm, twelve were treated by ESWL initially, and one by surgery. Of the 12 cases treated initially by ESWL, 4 became stone free, 4 remained with small fragments, and 1 remained with large fragments. Two patients were operated on because of poor response to ESWL and 1 patient lost kidney function because of prolonged obstruction. Disintegration of cystine stones >25 mm required an average of 8,522 shock-waves in 4.33 sessions. The problems associated with application of ESWL monotherapy to cystine stones are presented. © 1990 Cahners Publishing Company, A division of Reed Publishing USA.