Nephrolithiasis is a common condition affecting nearly 5 percent of U.S. men and women during their lifetimes. Recurrent calculi can be prevented in most patients by the use of a simplified evaluation, reasonable dietary and fluid recommendations, and directed pharmacologic intervention. Serum studies and 24-hour urine collections are the mainstays of metabolic investigation and usually are warranted in patients with recurrent calculi. Although some stones are the result of inherited conditions, most result from a complex interaction between diet, fluid habits, and genetic predisposition. Calcium-sparing diuretics such as thiazides often are used to treat hypercalciuria. Citrate medications increase levels of this naturally occurring stone inhibitor. Allopurinol can be helpful in patients with hyperuricosuria, and urease inhibitors can help break the cycle of infectious calculi. Aggressive fluid intake and moderated intake of salt, calcium, and meat are recommended for most patients.