The intake of marine n-3 PUFA has been shown to decrease the risk of CVD in a number of studies. Since the development of CVD is often a lifelong process, marine n-3 PUFA intake early in life may also affect the development of later CVD. The aim of the present study was to investigate the association between maternal intake of marine n-3 PUFA during the second trimester of pregnancy and factors associated with cardiometabolic risk in the 20-year-old offspring. The study was based on the follow-up of the offspring of a Danish pregnancy cohort who participated in a study conducted from 1988 to 1989. A total of 965 pregnant women were originally included in the cohort and detailed information about the intake of marine n-3 PUFA during the second trimester was collected. In 2008-9, the offspring were invited to participate in a clinical examination including anthropometric, blood pressure (BP) and short-term heart rate variability measurements. Also, a fasting venous blood sample was drawn from them. Multiple linear regression modelling, using the lowest quintile of marine n-3 PUFA intake as the reference, was used to estimate the association with all outcomes. A total of 443 offspring participated in the clinical examination. No association between the intake of marine n-3 PUFA during the second trimester of pregnancy and offspring adiposity, glucose metabolism, BP or lipid profile was found. In conclusion, no association between the intake of marine n-3 PUFA during the second trimester of pregnancy and the factors associated with cardiometabolic risk in the 20-year-old offspring could be detected.