Twenty children with juvenile recurrent parotitis, between 3 months and 16 years of age at onset, were followed up over a period of 7 to 22 years. Radiologic, histopathologic, cytologic, immunologic, and bacteriologic studies were performed to investigate the cause of sialectasis, commonly found in juvenile recurrent parotitis, and the pathogenesis of the disease. It was considered that a combination of a congenital malformation of portions of the salivary ducts and infections ascending from the mouth following dehydration of the children are contributory to the pathogenesis of the disease. The results of the investigations into the cause of the disease appear to exclude an auto-immunologic response or an allergic condition, an immature immune response, mumps, a sensitivity to upper respiratory tract infection, and familial factors.