This study focuses on young children's chronic undernutrition and its association with maternal sensitivity, sociodemographic variables, children's play, and problem-solving measures. Data were obtained with home observations and laboratory procedures on 85 mothers and infants (M age = 18 months) in a low-income urban population in Santiago, Chile. Maternal sensitivity was correlated with maternal education, maternal weight, and marital satisfaction. Observed in a variety of maternal roles, maternal sensitivity was also significantly associated with children's nutritional status, attachment security, and mastery behavior. These findings demonstrate the relevance of the maternal sensitivity construct outside industrialized societies and underline the need for intervention strategies to extend beyond nutritional supplementation to address deficits of maternal care associated with specific caregiver's roles.