Three female siblings aged 6, 4, and 2 years with the clinical syndrome of chronic granulomatous disease had frequent hospital admissions for serious bacterial infections, including pneumonia, liver abscesses, pyoderma, keratoconjunctivitis, draining adenitis, septicemia, and anemia. All three children were immunologically competent. Liver biopsy specimens in two of the three showed "chronic granulomatous reaction." Polymorphonuclear leukocytes from the patients showed impaired bactericidal ability when incubated with Staphylococcus aureus. Their leukocytes showed decreased ability to reduce nitroblue tetrazolium (NBT) dye compared with normal cells. The X-linked mode of transmission found in males with fatal chronic granulomatous disease is unlikely in these cases even if the Lyon hypothesis is considered. An autosomal locus acting either as homozygous recessive or dominant with variable expression would explain the occurrence of this disorder in females.