Motor development reflects the general health status of the child and affects other areas of development. It is influenced by biological and family characteristics especially in infancy and early childhood, and by environmental conditions in preschool age. We assessed the effect of several family and environment characteristics on gross motor developmental items included in the Denver-II test on 2,042 healthy children. Increasing maternal age and education were associated with later achievement in several items after age 12 months while socioeconomic status, sex and birth rank did not show a clear effect. Our observations suggest in a relatively homogenous urban population, few external factors affect gross motor development in preschool children.