OBJECTIVES: The objective of this study was to determine serum perfluorooctanoic acid (PFOA) concentrations and to investigate the relationship of lifestyle, health status and work-related factors among workers at manufacturing companies with possible occupational exposure to PFOA. METHODS: The study subjects were 315 workers (male 203, female 112) of manufacturing companies with possible exposure to PFOA from August to December, 2007. A questionnaire was administered to investigate lifestyle and work-related factors. Serum PFOA concentrations were analyzed by LCMS/ MS, and liver function and total cholesterol were also tested. RESULTS: Serum PFOA concentrations ranged from 1.0 to 40.9 ng/mL (mean 8.0 ng/mL). Serum PFOA concentrations increased with age. Male workers had higher PFOA concentration than female workers (male 9.0 ng/mL; female 6.3 ng/mL). According to stepwise multiple regression analysis, factors significantly associated with PFOA concentration were male, being older, higher total cholesterol, and lower body mass index. Adjusted for age and gender by logistic regression, dyeing and finishing textiles had significantly higher odds ratio (OR) of 6.16, and moulding patterns, moulds and industrial patterns (OR=4.84), sections for ships (OR=3.87), and plastics synthetic leather (OR=10.05) had marginally significantly high odds ratios. CONCLUSIONS: This study demonstrated the factors affecting serum PFOA concentration of workers at manufacturing companies. Further study is needed to ensure the effect of occupational exposure on serum PFOA concentration.