BACKGROUND: Impaired fetal growth is independently associated with an increased risk of cardiovascular events in adulthood. Prevention strategies that can be implemented during adulthood have not been identified. OBJECTIVE: The objective was to determine whether habitual omega-3 (n-3) fatty acid intake is associated with the rate of increase of carotid intima-media thickness during adulthood in individuals with impaired fetal growth. DESIGN: This was a population-based, prospective cohort study of 1573 adults in Finland. Carotid intima-media thickness was assessed in 2001 (at ages 24-39 y) and in 2007. Participants were categorized as having had impaired fetal growth (term birth with birth weight <10th percentile for sex or preterm birth with birth weight <25th percentile for gestational age and sex; n = 193) or normal fetal growth (all other participants; n = 1380). Omega-3 fatty acid intake was assessed by using a food-frequency questionnaire and on the basis of serum fatty acid concentrations. RESULTS: In multivariable models, the 6-y progression of carotid intima-media thickness was inversely associated with dietary omega-3 fatty acids in those with impaired fetal growth (P = 0.04). Similarly, serum omega-3 fatty acid concentrations were inversely associated with the 6-y progression of carotid intima-media thickness in those with impaired fetal growth (P = 0.04) but were not noted in those with normal fetal growth (P = 0.94 and P = 0.26, respectively). CONCLUSION: Dietary intake of omega-3 fatty acids is associated with a slower rate of increase in carotid intima-media thickness in those with impaired fetal growth.