The frequency and chronological distribution of enamel hypoplasias were assessed in a Roman Period population of the Wielbark culture from Rogowo, northern Poland, dated to the 2nd century ad. Hypoplasias were recorded on permanent incisors, canines, and premolars of 52 skeletons. The position of linear defects on the crown surface was measured and then converted to the age of occurrence using two methods: a conventional method that employs the chart of enamel development for the permanent teeth, constructed by Massler et al. (1941) in Swärdstedt's (1966) modification, and the method by Goodman & Song (1999), which corrects for hidden cuspal enamel. Hypoplastic defects were found in 48.1% of examined cases. Linear defects [linear enamel hypoplasias (LEH)] were observed in 38.5% of individuals and in 22% of investigated teeth. The chronological distribution of LEH according to the conventional method revealed two peaks of defects: one at 2.6–3.0 years of age and the other at 4.1–4.5 years of age. The method that accounts for hidden cuspal enamel also provided two peaks, but they occurred at later ages: 3.0–4.0 and 4.6–5.0 years of age. The prevalence of hypoplasia in the Rogowo population in comparison with other European populations of the Roman Period seems to be rather low for both individuals and teeth affected. This may indicate advantageous living conditions, which are supported by archaeological data that suggest general well‐being of the Wielbark people. Copyright © 2011 John Wiley & Sons, Ltd.