Atopic dermatitis (AD) is the most common chronic inflammatory skin disease, mainly caused by exposure to environmental pollutants. In this study, specific substances were analyzed in the blood and urine of mothers and children to investigate the association between AD and environmental factors, and as a result, 7 substances were identified as risk factors for respiratory diseases including allergic diseases. Therefore, the endocrine-disrupting chemical phthalate was identified as one of the risk factors for respiratory diseases including allergic diseases, and among various phthalate-based substances, mono-n-Butyl phthalate (MnBP) was selected as the main research target to determine whether it was related to the occurrence of AD. In this study, in order to determine the effect of MnBP on AD, a study was conducted using the human keratinocyte strain HaCaT Cell. First, WST-1 experiments on MnBP were conducted to evaluate cytotoxicity at various concentrations and to identify the non-toxic range. In order to elucidate the mechanisms by which AD is induced, the expression of proinflammatory cytokines (GM-CSF, TNF-α, IL-1β), chemokines (MCP-4/CCL13, RANTES/CCL5), and Th2 promoting cytokines (TSLP, IL-25) was analyzed using a reverse transcription polymerase chain reaction (RT-PCR) technique. Consequently, MnBP was found to increase the expression of proinflammatory cytokines, chemokines, and Th2 promoting cytokines, and MnBP in particular was found to be closely related to the occurrence of AD. These findings contribute to investigating the effects of exposure of environmental pollutants such as MnBP on AD and suggest that they can provide useful basic data for preventing and developing treatment strategies for future diseases.