Preterm delivery is a risk factor for suboptimal neurodevelopment. Pregnancies conceived after medically assisted reproduction-which includes invitro fertilization, with or without intracytoplasmic insemination, and induction of ovulation followed by intrauterine insemination or timed intercourse-have a higher risk of preterm delivery. Few studies have evaluated the outcome at >2 years of age of such preterm-born children. To evaluate neurodevelopmental outcome at 5½ years of age of children born preterm according to the mode of conception (spontaneous vs medically assisted reproduction). A total of 4349 children born between 24 and 34 weeks of gestation who survived to 5½ years of age in the 2011 French prospective national cohort study "EPIPAGE-2" were included: 814 in the medically assisted reproduction group (433 by invitro fertilization, with or without intracytoplasmic insemination, and 381 by induction of ovulation) and 3535 in the spontaneously conceived group. The studied neurodevelopmental outcomes were sensory (hearing and vision) impairments, cerebral palsy, cognition, and developmental coordination disorders. Multivariate analyses were performed with generalized estimating equation models adjusted for gestational age, antenatal steroids, and social characteristics. All analyses were performed following multiple imputation. Sensitivity analyses were performed with the populations of singletons and cases with complete data. No differences in cerebral palsy (adjusted odds ratio, 1.00; 95% confidence interval, 0.67-1.49), neurodevelopmental impairment (adjusted odds ratio, 1.09; 95% confidence interval, 0.82-1.45), or developmental coordination disorders (adjusted odds ratio, 0.75; 95% confidence interval, 0.50-1.12) were found between children born following medically assisted reproduction and children born following spontaneous conception after adjustment for sociodemographic factors. For proportions of children with an intelligence quotient below 1 and 2 standard deviations, there were no differences between those born after medically assisted reproduction and those born after spontaneous pregnancy (respectively, adjusted odds ratio, 0.99; 95% confidence interval, 0.80-1.23 and adjusted odds ratio, 1.14; 95% confidence interval, 0.83-1.56). In subgroup analyses, no differences were observed between children born following induction of ovulation or invitro fertilization and those conceived spontaneously. Sensitivity analyses were consistent with the main results. In this cohort of preterm-born children, there was no evidence of an impact of the mode of conception on neurodevelopmental outcomes at 5½ years of age.