BACKGROUND Atopic dermatitis (AD) is a chronic inflammatory skin disease. Clusterin is a sensitive cellular biosensor of oxidative stress and has been studied as a marker to assess inflammatory diseases. The clusterin levels in AD have not been evaluated thus far. OBJECTIVE We evaluated serum clusterin levels in children with AD and assessed the relationship between serum clusterin levels and the severity of AD. METHODS The study enrolled a total 140 children, of whom 100 had AD (n = 100) and 40 were healthy (n = 40). The severity of AD was scored by using the SCORing Atopic Dermatitis (SCORAD). Total serum immunoglobulin E and specific immunoglobulin E levels against egg whites, cow's milk, peanuts, soybeans, wheat, and Dermatophagoides farinae were measured. Clusterin levels in serum were measured by enzyme-linked immunosorbent assay. RESULTS The mean (interquartile range) age of the children was 5.1 years (1.3-8.4 years), and 92 (69.3%) of the children were boys. The mean (standard deviation) SCORAD index was 50.4 ± 17. The mean (standard deviation) clusterin level of children with AD was higher than that in the healthy control group children (148.13 ± 4.3 pg/mL versus 144.85 ± 5.1 pg/mL; p = 0.001). Serum clusterin levels were correlated with the SCORAD index (r = 0.327, p = 0.002). CONCLUSIONS The serum clusterin level was higher in children with AD than in the healthy control group and increased with the severity of AD. Serum clusterin may be a candidate molecule that reflects AD and its severity.