A report was made of three patients who exhibited pronounced heptosplenomegaly at the time of hospital admission: a six-year-old girl and two brothers, 1 year 4 months and 4 years 4 months of age. As is typical for Niemann-Pick disease, foam cells were found in the bone marrow and the liver biopsy specimens for the three patients. Since, however, none of the children had syptoms involving the central nervous systems, the disease must have been the rare B form of Niemann-Pick disease, the infantile chronic-visceral form. In all three patients, laboratory findings indicated a disturbance in hepatic function. The characteristic pulmonary involvement associated with the infantile form was found only in the two brothers, and then in a follow-up examination one year later. The reduced speed of nerve conduction established in the two brothers suggested subclinical involvement of the peripheral nervous system in the disease process. Electron-microscopic examinations of liver biopsies showed various forms of lipoid storage: lipoid bodies with loose, membranous structures and bodies with dense, concentrically arranged lamellae.