The symptoms of atopic dermatitis (AD) are often aggravated by stress, and AD can also lead to psychological stress due to social isolation and discrimination. The salivary cortisol level reflects psychological stress, and it is a good index to assess chronic stress. In this study, we measured the salivary cortisol levels in patients with AD (n = 30) and compared them with those of healthy control subjects (n = 42). AD patients were also evaluated for general disease severity using the Scoring Atopic Dermatitis (SCORAD) index. The serum levels of TARC, total IgE, and lactate dehydrogenase (LDH) and peripheral blood eosinophil counts were measured by laboratory tests. The Skindex-16 was used as a skin disease-specific, quality of life measure, instrument. The results showed that the saliva cortisol level was significantly higher in AD patients compared to healthy subjects (P < 0.01). The salivary cortisol level was significantly correlated with the SCORAD index (r = 0.42, P < 0.05) while the serum TARC and LDH levels were positively correlated with the SCORAD index. However, no statistically significant correlations were observed between the salivary cortisol level and Skindex-16. These results suggest that the saliva cortisol level is therefore a useful biomarker to evaluate the stress in AD patients.