A metabolic etiology is the most common cause for pediatric kidney stones. Appropriate evaluation of affected children should include assessment of stone type, if available, and assessment of predisposing factors in all cases. This review discusses the metabolic disorders that lead to nephrolithiasis with respect to the development of calcium, uric acid, struvite, and cystine stones. Environmental and hereditary factors are summarized to provide a guide in the evaluation of pediatric stone formers.