Background: High intakes of trans fatty acids (TFA) have been found to exert an undesirable effect on serum lipid pro®les, and thus may increase the risk for cardiovascular disease. Objective: Investigation of the association between TFA intake and serum lipids. Design: Cross-sectional study in eight European countries (Finland, France, Greece, Iceland, The Netherlands, Portugal, Spain, Sweden) among 327 men and 299 women (50 ± 65 y). Using a dietary history method, food consumption was assessed and TFA intake was calculated with recent ®gures on TFA levels of foods, collected in the TRANSFAIR study. Results: Mean ( AE s.d.) TFA intake was 2.40 AE 1.53 gaday for men and 1.98 AE 1.49 gaday for women (0.87 AE 0.48% and 0.95 AE 0.55% of energy, respectively), with the highest consumption in Iceland and the lowest in the Mediterranean countries. No associations were found between total TFA intake and LDL, HDL or LDLaHDL ratio after adjustment for cardiovascular risk factors. Additional adjustment for other fatty acid clusters resulted in a signi®cant inverse trend between total TFA intake and total cholesterol (P trend`0 .03).The most abundantly occurring TFA isomer, C18:1 t, contributed substantially to this inverse association. The TFA isomers C14:1 t9, C16:1 t9 and C22:1 t were not associated or were positively associated with LDL or total cholesterol. Conclusions: From this study we conclude that at the current European intake levels of trans fatty acids they are not associated with an unfavourable serum lipid pro®le.