BACKGROUND AND OBJECTIVES: Children born very preterm (VPT) are at high risk of cognitive impairment that impacts their educational and social opportunities. This study examined the predictive accuracy of assessments at 2, 4, 6, and 9 years in identifying preterm children with cognitive impairment by 12 years. METHODS: We prospectively studied a regional cohort of 103 children born VPT (≤32 weeks’ gestation) and 109 children born term from birth to corrected age 12 years. Cognitive functioning was assessed by using age-appropriate, standardized measures: Bayley Scales of Infant Development, Second Edition (age 2); Wechsler Preschool and Primary Scale of Intelligence (ages 4 and 6); and Wechsler Intelligence Scale for Children, Fourth Edition (ages 9 and 12). RESULTS: By 12 years, children born VPT were more likely to have severe (odds ratio 3.9; 95% confidence interval 1.1–13.5) or any (odds ratio 3.2; 95% confidence interval 1.8–5.6) cognitive impairment compared with children born term. Adopting a severe cognitive impairment criterion at age 2 under-identified 44% of children born VPT with later severe impairment, whereas a more inclusive earlier criterion identified all severely affected children at 12 years. Prediction improved with age, with any delay at age 6 having the highest sensitivity (85%) and positive predictive value (66%) relative to earlier age assessments. Inclusion of family-social circumstances further improved diagnostic accuracy. CONCLUSIONS: Cognitive risk prediction improves with age, with assessments at 6 years offering optimal diagnostic accuracy. Intervention for children with early mild delay may be beneficial, especially for those raised in socially disadvantaged family contexts.