Background: Kawasaki disease is a systemic vasculitis predominately affecting coronary arteries. Hemophagocytic lymphohistiocytosis can complicate the course of Kawasaki disease. Rare cases of secondary hemophagocytic lymphohistiocytosis occurring during the acute phase of Kawasaki disease have been reported. Case Report: We report here a 4 month-old girl with diffuse coronary ectasia and secondary hemophagocytic lymphohistiocytosis occurring during the acute phase of incomplete Kawasaki disease. Conclusion: Due to the large overlap in clinical symptoms, the presence of atypical findings for Kawasaki disease should suggest the possible diagnosis of hemophagocytic lymphohistiocytosis in these patients.