Objective: To estimate the intake of ruminant trans fatty acids (TFA) in the Danish population aged 1 - 80 years. Design: Descriptive study. Subjects: A sex- and age-stratified random sample drawn from the Danish Civil Registration System. A total of 3098 participants (51% female) aged 1 - 80 years were included. The participation was 66%. Dietary information: A 7-day dietary record. Results: The estimated median intake of ruminant TFA was 1.4 g/day with the 80% central range being from 0.9 to 2.1 among children aged 1 - 6 years and 1.6 g/day ( 1.0 - 2.4) among children aged 7 - 14 years. The median TFA intake was 1.8 g/ day (0.9-2.9) among adults aged 15 - 29 years and among adults aged 30 - 80 years. The intake expressed as percentage of energy intake was 0.8, 0.6, 0.7, and 0.7, respectively. Dairy products were the main source of ruminant TFA. Conclusions: The median intake of ruminant TFA in the Danish population aged 1 - 80 years is estimated to be 1.7 g/ day (0.9-2.7), corresponding to 0.7% of energy intake (0.5 - 1.0), with dairy products being the main source of ruminant TFA.