Objective: We conducted the present study to evaluate associations between prenatal exposure to environmental manganese and psychomotor development in children from the general population in Taipei, Taiwan. Methods: The study is a part of the Taiwan Birth Panel Study. A total of 132 pairs of parents and their full-term babies were selected into this study. The Comprehensive Developmental Inventory for Infants and Toddlers (CDIIT) was conducted at the age of six months. The CDIIT was used to assess development in the areas of cognition, language, motor (including gross motor and fine motor), social, and self-help of children. Samples of cord blood were analyzed by an Agilent 7500C ICP-MS. Regression models and adjusted means were used to evaluate the association of exposure to manganese and psychomotor development. Results: The fine-motor developmental quotients (DQ) of the CDIIT were significantly influenced by the level of manganese (crude β=-7.0, SE=2.5); the reverse relationship, however, was slightly diminished after adjustment (adjusted β=-6.0, SE=2.5). Based on logistic regression models, the results corresponded with the linear regression models (crude OR=3.20, 95% CI=1.31-7.85; adjusted OR=3.02, 95% CI=1.18-7.76). In addition, the manganese concentration was separated by every 25% and analyzed though adjusted means. The relationship between manganese levels and fine-motor DQ showed an inverted U shape. Conclusion: Fetuses may be vulnerable to environmental manganese exposure, particularly in terms of motor performance at the early age of six months. Some confounding factors, however, could not be excluded. Thus, further research is necessary to verify our findings. Nonetheless, to prevent the risk of poorer psychomotor development, we advise pregnant women to avoid exposure to excessive manganese in ordinary life.