Kawasaki disease (mucocutaneous lymph node syndrome) (MCLS) is an apparently infectious disease, an etiological agent of which has not been established, with peak age incidence at about 1 year, but with progressively fewer cases occurring into the fourth decade. Early clinical features include fever, rash, conjunctival injection, dry reddened lips, oropharyngeal reddening, enlarged cervical nodes, and swelling and redness of hands and feet. Peeling of skin of fingers and toes, arthralgia, and marked thrombocytosis are frequent 1-2 weeks after onset. Myocarditis, cardiac valvulitis, and lymphocytic or mixed interstitial infiltration of pancreas, renal, splenic, and hepatic hilar regions are seen in the early phase, but arteritis, typically of extraparenchymal arteries, is the most important aspect of MCLS, hence the term infantile periarteritis nodosa, formerly applied to fatal cases of MCLS. Thrombosis of coronary artery aneurysms is the most common cause of death (rate about 0.5%). The peak time of death is 3-4 weeks from onset, but death from coronary occlusion has been seen as late as 14 years after the acute phase. Aneurysmal rupture with hemopericardium or retroperitoneal hemorrhage is rare, as are late brachial, iliac, or other arterial aneurysms. Pathological features of MCLS in the early and later stages are described and illustrated, and the epidemiologic, etiologic, forensic, and other aspects of the disease are discussed.