PURPOSE: Staphylococcus aureus and its exotoxins have been regarded as having an influence on atopic dermatitis(AD). We aimed to examine the prevalence of S. aureus in the AD lesion, the types of the exotoxins, and the relationship between S. aureus and AD. METHODS: AD patients(n=32) and a normal control group(n=20) were enrolled. The severity of AD was measured by SCORAD index. Through skin culture and PCR, we tried to identify S. aureus and its exotoxins. RESULTS: S. aureus was isolated from 18(56 percent) out of 32 AD patients and its exotoxins were identified from 10(31 percent) out of them. The exotoxin types were as follows; sea in 4, eta in 3, sea+tst-1 in 1, sea+see in 2 patients. On the contrary, S. aureus was isolated from only 1(5 percent) out of 20 subjects of the normal control group, and its exotoxin type was sea. The SCORAD index in the S. aureus(+) group was higher than in the S. aureus(-) group, however it was not significant.(44+/-14.2 vs 38+/-17.1, P= 0.304) The SCORAD index was higher in the exotoxin(+) group than in the exotoxin(-) group(49+/-11.2 vs 38+/-16.2, P<0.05). The prevalence of S. aureus and its exotoxins in the AD group was higher than in the normal control group(P<0.001, P<0.05, respectively). The difference of SCORAD index was significant between the exotoxin(+) group and the exotoxin(-) group, but not between the S. aureus(+) group and S. aureus(-) group.(P<0.05, P= 0.304, respectively) CONCLUSION: The exotoxins of S. aureus were found to influence the severity of AD.