Kawasaki disease (KD) is an acute vasculitis of infants and young children that is associated with bilateral nonexudative conjunctivitis during the acute illness. Epidemiologic evidence has suggested an infectious cause but the etiology of KD remains unknown. We examined conjunctival biopsy specimens from seven patients with typical KD to characterize the pathologic changes during the acute disease. Light microscopic examination revealed nonspecific, mild inflammatory changes that included vascular dilatation, infiltration with scattered lymphocytes, increased numbers of plasma cells in the conjunctival stroma, and increased prominence of goblet cells in the epithelium. No pathogens were identified by special stains for bacteria and rickettsiae, nor were viral particles seen by electron microscopy. We conclude that the conjunctivitis of acute KD is characterized by vascular dilatation with a mild mononuclear cell response with no pathognomonic features. The conjunctiva can be readily sampled in these patients and biopsy may prove useful in selected patients to exclude other clinical entities in the differential diagnosis.