Idiopathic calcinosis of the scrotum has been found in 14 patients, bringing the total number of proved and presumptive cases to 35. The lesions are usually multiple, asymptomatic nodules of the scrotal skin which begin in childhood or early adult life, increase in size and number, and sometimes break down to discharge chalky contents. They are unrelated to cysts, any known predisposing factor, or calcification elsewhere. Clinically they are most often misdiagnosed as cysts. Excision appears to be the treatment of choice, if treatment is requested, but other lesions may develop in the residual scrotal skin.