The author reviews the epidemiological, etiological aspects of stone disease of the urinary tract, and prophylactic treatment. The occurrence of urolithiasis has increased considerably since the second world war and now affects 10% of the adult male and 4% of the adult female population. In Norway the yearly incidence of patients presenting with urinary stone colic in general practice is two per 1,000 inhabitants. Urinary calculi form when the concentration of the crystal-forming substances such as calcium oxalate, calcium phosphate, uric acid and cystine exceed their solubility. Important risk factors for stone formation are low fluid intake and high consumption of animal protein. Etiological examination and stone prophylactic treatment should reflect the most prevalent types of stone disease. An examination programme that probably can reveal one or several causes of the stone disease in about 60-70% of the patients is described. The recommended examinations car be performed in general practice. Prophylactic treatment in terms of dietary advice and fluid intake is suggested. In patients with a high recurrence rate of stone formation prophylactic drug treatment with tiazid or alluopurinol should be considered. The beneficial effect of the treatment is well documented.