A cystic calculus approximately 6 cm in diameter was diagnosed by ultrasonography and endoscopy in a 12-year-old Trakehner gelding with a history of haematuria and dysuria. Transurethral endoscopic lithotripsy with electrohydraulic shock waves was performed as a minimally invasive treatment option. Fragmentation of the calculus was achieved, the fragments of the calculus left in the bladder and excretion assisted by infusion of Ringer's solution. Twenty-four hours after the third lithotripsy, the horse suffered a recurrence of dysuria and pollakiuria due to partial obstruction of the urethra by the calculus fragments. The treatment was repeated within the urethra until clearance of the fragments was achieved. The sharp fragments had produced a zone of urethral mucosal trauma, approximately 10 cm in length. At the follow-up visit 4 weeks later, the patient had developed inflammation and swelling of the urethral mucosa, which was successfully treated with a 14 day course of anti-inflammatory drugs. This resulted in normal urination. At the last follow-up, the horse had been recurrence-free for 12 months.