An 11 year old Chinese boy developed a unilateral cervical mass associated with pronounced eosinophilia and a marked increase in IgE concentrations. A biopsy sample showed massive eosinophilic tissue infiltration consistent with Kimura's disease. This disorder should be suspected when the clinical triad of painless unilateral cervical adenopathy, hypereosinophilia, and hyper-IgE is present, particularly in male Asian patients.