Introduction: In experiencing epidemiologic transition, Indonesia faces emerging nutrition problems. Methods: Among the dietary lifestyle changes over the years is the rising consumption of fats and oils, including trans fatty acids. Intake of these fatty acids from ruminant meats, hydrogenated vegetable oils and fried foods is known to have detrimental effects on serum lipoprotein cholesterol levels. The purpose of this study was to determine the effects of trans fatty acid intake on blood lipid profile. A prospective cohort study was conducted on 388 workers at an on-shore oil company in East Kalimantan. Results: The mean intake of trans fatty acid was 0.48% of the total dietary calories. Fried foods contributed most to the total trans fatty acid consumed at 0.20% of the total calories. Trans fatty acid intake from ruminant products, and margarine/ hydrogenated vegetable oil products were 0.09% and 0.06% of calories, respectively. The high consumption of fried foods is associated with risks of hypertriglyceridemia (RR: 1.41, 95%CI 1.06; 1.86), high ratio of total cholesterol/ HDL-C (RR: 1.98, 95%CI 1.00; 3.98) and dyslipidemia (RR: 1.35, 95%CI 1.00;1.84). Every additional one percent of saturated fatty acid intake is associated with an increase in trans fatty acids amounting to 0.03% of total calories (r = 0.320, p = 0.000). Conclusion: These results suggest that a reduction in consumption of fried foods will be of benefit as it will reduce intake of both saturated and trans fatty acids. Further studies are recommended to determine the intake of trans fatty acids and their health effects on other population groups in Indonesia.