An outbreak of acute crural myalgia in children is reported. The severe calf pain followed an influenza-like episode, with subsequent complete recovery. Laboratory studies in most cases showed elevated creatine phosphokinase and SGOT values, with a low peripheral white blood cell count. Electromyographic studies were normal. Results of one muscle biopsy were normal. This postviral myalgia is a distinctive syndrome only recently being recognized in the United States.