Osteomyelitis is a rare complication after varicella. It should, however, be considered in any child who develops pain in a limb during or after a varicella infection. An 18 month old boy with a five day history of varicella infection was hospitalized. Movement of his right arm made him cry intensively. Blood cultures showed growth of group A beta haemolytic streptococcus. The day after admission to hospital the bone scintigrams showed increased activity in the right humeral diaphysis consistent with osteomyelitis, and penicillin therapy was started. On radiograms of the right humerus performed on the second day, no pathological changes could be shown. Radiograms after ten days showed irregular osteolytic lesions in the upper part of the humeral diaphysis. Clinically, the boy improved rapidly and could be dismissed from hospital after 17 days. Follow-up radiograms showed slowly normalized conditions, and five months after the start of symptoms, no pathological changes should be demonstrated.