Purpose: For decades, consistent associations between breastfeeding and children’s neurodevelopement have been attributed to breastmilk content in long-chain polyunsaturated fatty acids (LC-PUFAs). However, the beneficial effect of LC-PUFA enrichment of infant formula on neurodevelopment remains controversial. This study examined the association of LC-PUFA enrichment of infant formulas with neurodevelopment up to age 3.5 years. Methods: Analyses were based on 9,372 children from the French nationwide ELFE birth cohort. Monthly from 2 to 10 months, parents declared their infant’s feeding mode, including breastfeeding and the name of the infant formula, which allowed for identifying formulas enriched in arachidonic (ARA), eicosapentaenoic (EPA) and/or docosahexaenoic (DHA) acids. Neurodevelopment was assessed at age 1 and 3.5 years with the Child Development Inventory (CDI-1 and CDI-3.5); at 2 years with the MacArthur-Bates Communicative Development Inventories (MB-2); and at 3.5 years with the Picture Similarities subtest of the British Ability Scale (BAS-3.5). Associations were assessed by linear regression adjusted for any breastfeeding duration and main confounding factors, including socioeconomic characteristics. Results: One third of formula-fed infants consumed LC-PUFA–enriched formulas. Most of these formulas were enriched in both DHA and ARA, and about 10% of infants consumed formula further enriched in EPA. LC-PUFA enrichment of infant formula was not associated with neurodevelopmental scores at age 1 (CDI-1, -0.16 [-0.39, 0.07]), age 2 (MB-2, 0.78 [-0.33, 1.89]), or age 3.5 (CDI-3.5, -0.05 [-0.27, 0.17]; BAS-3.5, -0.93 [-2.85, 0.98]). Conclusion: In the ELFE study, LC-PUFA enrichment of infant formula was not associated with neurodevelopmental scores up to 3.5 years.