Resumo. ABSTRACT Little is known about the impact of environmental factors and daily tasks for the infant development which the adolescent mother is exposed. Therefore the present study was to identify associations and predictors of motor and cognitive development of infants of adolescent and adult mothers. Participated 40 babies aged between 0 and 18 months, 20 babies in each group - adolescent and adult mothers. Alberta Motor Infant Scale, Bayley Scale of Infant Development; Affordances in the Home Environment for Motor Development, Knowledge of Infant Development and Daily Activities of Infant was used for assessments. A strong association between motor skills and cognition (r² = 0.88) in both groups was observed. The predictors of motor development in the adolescent mother group were paternal age, home space, the mother does not work outside the home, parents' educational level, number of toys and adults in the household, parenting practices and knowledge of parents The predictors of cognitive development were parents living together, the amount of rooms in the residence and parenting practices. In the adult mother group, the predictors of motor development were the cognitive development, caesarean birth, parents living together, amount of rooms in the residence and parenting practices. As predictors of cognitive development, remained in the regression model the motor development, number of days in the ICU, number of rooms in the residence and parental practice. Conclusions: The interdependence between cognition and motor skills, family and residence characteristics, and parenting practices were the main determinants of infant trajectory.