A group of 273 children with minor complaints was screened for idiopathic hypercalciuria by measurement of the urine Ca/Cr. Borderline or definitely high levels were noted in 17 of these children, 11 of whom were boys. More intensive metabolic studies were completed on four of these children and on three children who were noted to have symptomatic renal stones associated with idiopathic hypercalciuria. These studies suggest that IH, well recognized in adults, may have its origins in childhood and that appropriate management, if initiated in childhood, may have significant long-term benefits.