Multifocal osteomyelitis is considered an uncommon complication of acute osteomyelitis. Over a 3-year period, 136 infants and children who had a final diagnosis of acute osteomyelitis were reviewed, and multifocal osteomyelitis was detected in 27 (19%) patients. The major age peak of acute osteomyelitis was between 6 weeks and 3 years (46%). Two age peaks were found for multifocal disease-less than 6 weeks (38%), and 9 to 12 years (44%). Three patients with multifocal disease had septicemia and photon-deficient areas on bone scans. Another adolescent group had nonspecific bone and joint pain that in some cases persisted for more than 3 months and were finally diagnosed as multifocal osteomyelitis. Organisms were isolated in 15/27 (56%). Multifocal osteomyelitis is well recognized in the neonatel age group. However, it occurs more commonly than previously described in older patients. This higher incidence can most likely be attributed to the higher use of the radionuclide bone scan early in the disease and the high sensitivity of the scan for the detection of osteomyelitis.