Background: Extremely low weight has been associated with a high risk of sequelae or Neurodevelopmental disorders, including personality disorders and emotional distress.Objective: to learn the differences in neurodevelopment at 2 and 4 years of infants with a weight ≤1500g. Material and Methods: observational, analytical retrospective, comparative study of a cohort of children with a birth weight ≤1500g compared with children >1500g who attended the Pediatric Follow-up at the National Institute of Perinatology. BSID II and the Stanford-Binet Intelligence Scale by Terman-Merril 4 th ed were used.Results: 128 patients were included in the comparative analysis; significant differences were found in MDI and PDI of BSID II. For the group ≤1500 g presented a higher incidence in behavior (Orientation, Commitment and/or Emotional Regulation).In the Intelligence Scale, the group of children <1500g at birth presented a statistically significant difference in all cognitive abilities and IQ.Conclusions: At two and four years of age, children weighing <1500 grams have lower scores in neurodevelopment when compared to the group >1500 grams. Behavioral problems are a factor that influences MDI and PDI at two years of age.