Cystinuria is an autosomal recessive hereditary disorder associated with nephrolithiasis and its attendant complications. Traditional management aimed at increasing urinary cystine solubility using oral alkali, D-penicillamine, or mercaptopropionyglycine is often unsuccessful due to intolerable side effects. Two cystinuric patients intolerant of traditional therapy were treated with captopril for 1 year, resulting in a marked decline in urinary cystine excretion. Neither patient experienced recurrent nephrolithiasis or adverse drug effects. Captopril should be considered an alternative to traditional drug management of cystinuria.