OBJECTIVE To investigate the risk of communication impairments at age 18 and 36 months in children born early term (gestational weeks 37-38) and late preterm (gestational weeks 34-36). STUDY DESIGN A total of 39 423 children and their mothers participated in the Norwegian Mother and Child Cohort Study. The sample included 7109 children (18%) born early term and 1673 (4.2%) born late preterm. Information on gestational age and prenatal and postnatal risk factors was obtained from the Medical Birth Registry of Norway. Information on communication impairments was assessed using standardized questionnaires filled out by the mothers. Stepwise logistic regression analysis was applied to explore the associations between early term/late preterm birth and communication impairments at age 18 and 36 months. RESULTS Compared with children born at term, children born early term and late preterm had an increased risk of communication impairments at age 18 and 36 months. In early term, the aOR was 1.27 (95% CI, 1.12-1.44) at 18 months for communication impairments and 1.22 (95% CI, 1.07-1.39) at 36 months for expressive language impairments. In late preterm, the aOR was 1.74 (95% CI, 1.41-2.14) at 18 months and 1.37 (95% CI, 1.09-1.73) at 36 months. CONCLUSION Not only children born late preterm, but also those born early term, are at increased risk for communication impairments. Given the large number of children potentially affected, this may result in significant health care costs.