We examined the serum soluble IL-2 receptor and eosinophil cationic protein levels in patients with atopic dermatitis (n = 21), patients with urticaria (n = 12), and normal healthy individuals (n = 14). We found that both soluble IL-2 receptor levels and eosinophil cationic protein levels were significantly higher in atopic dermatitis than in urticaria or normal controls. Although both soluble IL-2 receptor levels and eosinophil cationic protein levels were significantly correlated with clinical severity scores in atopic dermatitis, the correlation between eosinophil cationic protein levels and clinical severity scores was higher than that between soluble IL-2 receptor levels and clinical severity scores. However, soluble IL-2 receptor levels, eosinophil cationic protein levels and clinical severity scores were not significantly correlated with IgE levels. The chronological changes of soluble IL-2 receptor and eosinophil cationic protein levels differ from patient to patient. However, levels of soluble IL-2 receptor and eosinophil cationic protein seem to parallel to each other in 65% of patients with AD. Measurement of serum eosinophil cationic protein or soluble IL-2 receptor levels may be a useful tool to monitor the short-term or long-term disease activity of atopic dermatitis in conjunction with clinical severity scores.