An infant with Kawasaki syndrome presenting with fever, rash, and a high percentage of neutrophils with toxic granulation is reported. The peripheral blood smears of the patient showed a high proportion of neutrophils with marked vacuoles and toxic granulations. The reactive changes in neutrophils could be helpful in the early detection of the disease, especially in infants younger than 6 months of age who are at high risk for development of coronary artery disease.