Preterm infants are at higher risk of developing hypothermia and complications from cold stress, resulting in high mortality and short-term morbidity. Our objective is to evaluate the association between admission temperatures of extremely low-gestational age neonates (ELGAN) (<29 weeks') and adverse short-term neurodevelopmental outcomes. In this retrospective study, we included ELGAN admitted to NICUs across Canada between April 2009 and September 2011, who underwent neurodevelopmental assessment at 18-21 months' corrected age. Of 2739 infants with a complete data set identified during the study period, 968 (35.3%) had admission temperatures ≤36.4 °C (hypothermia group), 1489 (54.5%) had temperature of 36.5-37.2 °C (normothermia group), and 282 (10.3%) had hyperthermia (≥37.3 °C). Their mean birth weight was 823 ± 230 g, 944 ± 227 g and 927 ± 223 g, respectively (p < 0.01). More than 50% of infants born at 23-24 weeks were in the hypothermic group compared to 28.5-36.1% at higher gestational ages. We found 39.5% of infants in the hypothermic group had primary composite outcome of death or severe neurodevelopmental impairment (sNDI). Multivariate logistic regression revealed an increased adjusted odd of primary composite outcome (OR = 1.32; 95% CI = [1.05, 1.66]) in the hypothermic group, compared to infants with normothermia on admission. In our cohort of ELGAN, hypothermia on admission was associated with increased risk of death or sNDI.