The report is based on observations covering 111 cases of bilateral staghorn calculi in the kidneys. Control examinatiions were carried out after 1–15 years. The number of patients treated conservatively weas 27, of whom 9 are still alive, 12 have died and there is no information about 6. Eighty-four patients were treated surgically. Depending on the patient's general state and the renal lesions, the operations were performed on one side in 47 cases, and bilaterally in 37 cases. Pyelotomy, pyelonephrotomy, nephrotomy and total nephrotomy were carrid out most frequently; 10 cases unilateral nephrectomy was carried out due to pyonephrosis. Fifty-two patients are alive, 17 have died. It is evident from the accomplished observdations that the conservative treatment is justified only in those cases in which surgical intervention, the basic therapy, is contraindicated. The surgical method should be chosen individually, relkying on the anatomical situation as well as on the shape and size of thie stone. The results are the better and the survival time the longer, the sooner the operation has bveen performed. The patients with bilateral staghorn calculi are to be operated in centres where haemodialysis is available at any time.