Gasoline and diesel are petroleum-derived liquid mixture as fuel in motor vehicle engines. In Taiwan, manganese concentration was detectable in gasoline and diesel, which may exhaust to air. This study was conducted to investigate the relationship between the concentration of manganese in cord blood and the density of petrol stations, a surrogate for manganese emissions from traffic gasoline consumption. In total, 1,526 consecutive births of full-term newborns without major congenital malformation were recruited from different levels of medical unit from May 2004 to July 2005. Questionnaires on demographic characteristics, medical history, and living environment, among other factors, were completed by newborns’ mothers after delivery. Cord blood samples were collected at birth and analyzed by inductively coupled plasma mass spectrometry. Petrol station density (PSD) within a 10-km buffer zone around each newborn’s residence, which was used as a surrogate for exposure to traffic-related manganese emissions, was calculated for 1,343 newborns using the Arc9 Geographic Information System. The geometric means of cord blood manganese and lead concentrations were 47.0 μg/L (GSD=1.4) and 12.6 μg/L (GSD=1.8), respectively. After adjusting for confounding factors, such as maternal education, gestational age, etc., the results of a multiple linear regression model indicated that cord blood manganese concentration was associated with petrol station density (p<0.0001). However, no such association was found for cord blood lead. This finding suggests that exposure to traffic-related air pollution might have led to fetal exposure to elevated manganese levels. Further research is warranted to explore the relationship of traffic-related manganese exposure with potential adverse health effects in fetal development.