['An inverse correlation between serum 25-hydroxyvitamin D concentration and atopic dermatitis (AD) severity has been suggested.', 'To determine if a statistically significant relationship exists between serum 25-hydroxyvitamin D concentration and AD severity.', 'A cross-sectional study was conducted of patients with AD who were 1 to 18 years of age. An objective Severity Scoring of Atopic Dermatitis (SCORAD) and a serum 25-hydroxyvitamin D concentration were measured for each subject. Statistical analysis was performed using appropriate univariate tests and multivariable models.', 'Ninety-four of 97 enrolled subjects were included in the analysis. Vitamin D deficiency (25-hydroxyvitamin D <20 ng/mL) was present in 37 subjects (39%), insufficiency (25-hydroxyvitamin D 21-29 ng/mL) in 33 (35%), and sufficiency (25-hydroxyvitamin D ≥30 ng/mL) in 24 (26%). The correlation between 25-hydroxyvitamin D concentration and SCORAD was not significant (r = -0.001; P = .99). A multivariate model showed that a lower serum 25-hydroxyvitamin D concentration was significantly associated with age 3 years or older (P < .0001), black race (P < .0001), and winter season (P = .0084).'] Does serum 25-hydroxyvitamin D concentration correlate with atopic dermatitis severity?