OBJECTIVE: To validate an instrument that assesses the severity of pruritus in patients of 2 to 7 years with atopic dermatitis. MATERIAL AND METHOD: A cross-sectional analytical study type validation of instrument was done from February 2017 to February 2018. The elaborated construct was submitted to expert's judgment; it was evaluated by the Kendall W coefficient. The factorial analysis was used to validity; and the reproducibility was evaluated through the Cronbach's alpha SPSS 24 was used. RESULTS: The instrument was applied to 39 patients, 69.2% of them were women; the median age was 4 years. The Kendall's coefficient was 0.63. The validity of content and construct was evaluated by the factorial analysis, where it has achieved two dimensions that explained 60% of the variance. The reliability measured by Cronbach's alpha was 0.82, and the internal consistency was 0.84 and 0.60 for each dimension. CONCLUSIONS: A valid, reliable and two-dimensional instrument was obtained to measure the severity of pruritus in pediatric patients with atopic dermatitis.