Exclusive breastfeeding coverage in Indonesia in 2022 was recorded at only 72.04%, while in East Nusa Tenggara Province it was 78.56%. In Kupang Regency in 2022, the achievement of exclusive breastfeeding will be 77.2%, which is still less than the national target indicator. Breastfeeding mothers who return to work are less likely to provide exclusive breastfeeding. How challenges can occur in efforts to provide exclusive breastfeeding, namely the environment and from the mother herself. This study aims to determine the influence of the workplace environment on the behavior of breastfeeding mothers who work as health workers. This research is quantitative research using a cross sectional approach. The sample from this research consisted of 84 respondents. In selecting samples using inclusion criteria, namely mothers who work as health workers who have babies aged 6 - 24 months in the Kupang Regency area. The research instrument used a questionnaire from January to March 2024. Data analysis used the chi square test. The results of the univariate analysis showed that the majority of workplace environments were categorized as Fair (53.6%). According to breastfeeding behavior, the majority of breastfeeding mothers chose to partially breastfeed (61.9%). According to the results of bivariate analysis, with a p value of 0.021. An unsupportive work atmosphere can influence the behavior of mothers who breastfeed exclusively. As a result, health institutions must help mothers more by providing appropriate social and physical facilities. In addition, written policies that regulate the rights of breastfeeding mothers must have clear technical instructions. All parties must be committed to creating a friendly environment for breastfeeding mothers. There is an influence of the work environment on breastfeeding behavior for health workers who breastfeed.