The purpose of our study was to examine deciduous tooth crown size in preterm children.The subjects consisted of 328 prematurely born (< 37 gestational weeks) white and black children and 1804 controls, who participated in the cross-sectional study of the Collaborative Perinatal Project (USA) in the 1960s and 1970s. Documents of the present research consisted of dental casts of the 6-12 years old children. Tooth crown measurements on canines and molars were performed on the dental casts with an electronic measuring device according to precise definitions generally quoted in the anthropological and genetic literature. For the results, the preterm and control groups were divided by sex and race.There were both increased and decreased mesiodistal and labiolingual tooth crown dimensions in prematurely born children, but no significant differences between the study groups was found.The findings of the present research suggest that short gestation is not associated with reduced deciduous tooth crown size as suggested by earlier studies and are parallel with our previous results of permanent tooth crown dimensions in prematurely born children. Boys showed clearly larger tooth crown sizes than girls within all preterm and control groups. This indicates that sexual dimorphism is apparent in its final form beginning some months after birth.