Importance: Although birth defects in children with congenital Zika syndrome (CZS) are expected to result in significant intellectual disabilities, the extent of delay and profiles of development have yet to be fully described. Objectives: To describe the neurodevelopmental profiles of children with CZS and to test whether prenatal and postpartum characteristics were associated with the severity of developmental delays. Design, Setting, and Participants: This is a case series of the trajectories of developmental, behavioral, and medical needs of 121 young children with CZS who were assessed at a specialized rehabilitation center in Recife, Brazil, beginning in January 2018 as part of 5-year longitudinal study. Children were included if they had serologic confirmation of Zika virus and met clinical criteria accompanied by parental report of suspected exposure to Zika virus during pregnancy. Exposures: Prenatal Zika virus exposure. Main Outcomes and Measures: The Brazilian version of the Bayley Scales of Infant and Toddler Development, Third Edition, was administered by trained assessors as part of an initial comprehensive assessment battery. Caregiver interviews and medical record reviews were conducted to gather basic demographic information and medical comorbidities. Linear regression was used to identify potential factors for development. Results: The sample included 121 young children (mean [SD] age, 31.2 [1.9] months; 61 [50.4%] girls). At age approximately 2.5 years, nearly all children in this sample demonstrated profound developmental delays across all domains of functioning, with a mean (SD) developmental age equivalent to approximately 2 to 4 months (eg, cognitive domain, 2.24 [3.09] months; fine motor subscale, 2.15 [2.93] months; expressive language subscale, 2.30 [2.52] months). A relative strength was found in receptive language, with scores on this scale significantly higher than most other domains (eg, cognition: t = 3.73; P < .001; fine motor: t = 6.99; P < .001). Head circumference at birth was the single strongest factor associated with outcomes across all developmental domains (eg, cognitive: ß = 1.41; SE, 0.67; P = .04; fine motor: ß = 1.36; SE, 0.49; P = .007). Conclusions and Relevance: The findings of this study provide important information regarding the severity of disability that these children and their families will experience. The findings also establish an initial point from which to monitor developmental trajectories, medical comorbidities (eg, seizures), effectiveness of interventions, and cumulative consequences on families.