Omega-3 docosahexaenoic acid (DHA) is a prominent component of neural tissue that accumulates most rapidly during the fetal brain growth spurt in the last trimester of pregnancy. Our trial supplementing infants born <29 weeks’ gestation with the estimated in-utero dose of DHA improved intelligence Quotient (IQ) by 3.5 points(1). The aim of this study was to explore the relationships of infant status of DHA and other key fatty acids with IQ scores. In the study, 656 infants born <29 weeks’ gestation at five Australian hospitals (2012-2015) were randomised to receive enteral 60 mg/kg/day DHA or a control emulsion from within 3 days of commencing enteral feeds to 36 weeks postmenstrual age. At 5 years’ corrected age, children were invited to undergo a Wechsler Preschool and Primary Scale of Intelligence (WPPSI). The relationships between WPPSI scores, and DHA, omega-6 arachidonic acid, omega-6 linoleic acid, and omega-9 oleic acid status of neonatal blood samples were explored. DHA intervention successfully increased infant DHA status. After confounding adjustment, DHA status at 36 weeks post-menstrual age (end of intervention) was positively associated with Full-Scale IQ (p=0.04) and Verbal Comprehension Index (p=0.04). An increase in DHA status from the 50th to 95th percentile (~3.1% to ~4.7% DHA) was associated with a 3.3-point increase in Full-Scale IQ and 2.6-point increase in the Verbal Comprehension Index. The omega-6 and omega-9 fatty acids examined were not associated with WPPSI scores. Positive associations between DHA and WPPSI scores are consistent with the findings of the randomised trial, suggesting neonatal blood DHA may be a modifiable risk factor to improve IQ.