A 40-year-old black man developed the primary features of Kawasaki disease, along with a pronounced distal motor and sensory neuropathy, abnormal electromyograms, and elevated creatine kinase levels. Results of the biopsy of a distal muscle showed myonecrosis, some type II grouping, immunoglobulin deposition in the sarcolemma, and disordered sarcomeric alignment with dilated T-tubules and terminal cisternae. Immunologic evaluation showed high concentrations of cryoglobulins and circulating immune complexes. It is possible that several manifestations of Kawasaki disease are mediated by immune complex deposition in vessels and tissues.