Background/aim: The aim of the Brazelton Neonatal Behavioral Assessment Scale (BNBAS) is to gather a comprehensive pro le of neonatal functioning by describing the full range of neonatal behavior, including competencies and strengths, as well as di culties or deviations. is instrument has proved to be of great clinical value by detecting infants at risk for later developmental problems. is work was conducted methodologically with the aim of a Turkish validity and reliability study of the BNBAS. Materials and methods: The study was conducted in a large tertiary hospital in Turkey. After establishing content and language validity, the BNBAS was applied to 380 newborns aged 1?3 days and test?retest analysis was performed for 60 newborns 52?55 days later in the rst phase. e validity and reliability study of the BNBAS included behavior and support subscales, while re ex items were not included. Results: In the study, 5 items were excluded from the original BNBAS a er the factor analysis. Cronbach alpha was found as 0.974 (30 items). The behavior subscale consisted of 23 items and the support subscale consisted of 7 items. Newborns showed good overall tone and activity level and low amounts of irritable behavior. Conclusion: It may be recommended to use the BNBAS as a valid and reliable measurement tool in neonatal behavioral evaluation by physicians and nurses.