Background <p>To assess the relationship between postnatal conditional growth and size and body composition at 24 months’ corrected age (CA) in children born moderate-and-late preterm (MLPT).</p> Methods <p>Children born MLPT (32⁺⁰-35⁺⁶ weeks’ gestation) were recruited to the Different Approaches to Moderate &amp; late preterm Nutrition: Determinants of feed intolerance, body composition, and development randomized trial from neonatal units in New Zealand. The relationships between growth in weight, length, and head circumference z-scores and body composition (fat mass (FM) and fat-free mass (FFM) z-scores) at discharge, 4 and 24 m and anthropometry and body composition at 24 m was assessed using conditional growth curve models.</p> Results <p>In 343 children with longitudinal data (mean (standard deviation) gestation 33.4 (1.0) weeks; birthweight 2120 (424) g), growth in size and body composition after hospital discharge, specifically FM z-score at 4 m and FFM z-score at 24 m, had stronger associations with size and body composition at 24 m than measures at or before discharge. Growth patterns were not different between moderate- and late-preterm infants (32–33 and 34–35 weeks) but differed between sexes, small-for-gestational-age ( &lt; 10^th percentile) and ethnicities.</p> Conclusion <p>In children born MLPT, growth in size and body composition after discharge is important for size at 24 months.</p> Impact <p><UnorderedList Mark="Bullet"> <ItemContent> <p>The influence of timing of growth on later size and body composition in children born moderate-and-late preterm is unknown.</p> </ItemContent> <ItemContent> <p>Growth in fat mass z-score at 4 months and fat-free mass z-score at 24 months had stronger associations with size and body composition at 24 months than measures at or before discharge.</p> </ItemContent> <ItemContent> <p>Growth in size and body composition after discharge is important for size at 24 months in children born moderate-and-late preterm.</p> </ItemContent> </UnorderedList></p>