ObjectiveTo assess the association between quality of stimulation in the family environment and child's cognitive development considering the impact of mother's schooling on the quality of stimulation. Methods A cross-sectional study comprising 350 children aged 17-42 months was carried out in central and peripheral areas of Salvador, Northeastern Brazil, in 1999. A socioeconomic questionnaire was used, along with the Home Observation for Measurement of the Environment Scale (HOME Inventory), and the Bayley Scale for Infant Development. Bivariate and multivariate analyses were carried out through linear regression at 5% level of significance. ResultsThere was a positive (β=0.66) and statistically significant association between quality of stimulation in the family environment and child's cognitive development. Part of the effect was mediated by the mother's working circumstances and educational level. It was verified that a better quality of stimulation is provided for those who come early in the birth order in family, and live with only a few others under five years of age. This pattern of stimulation is better among children who live with their parents and whose mothers have better education, have a job and a partner involved in the family environment. Conclusions Quality of stimulation in the family environment is crucial for child's cognitive development, besides the significant role of the available resources and family dynamics. The study findings show the pertinence to cognitive development of interventions which improve the quality of the environment and the child-caregiver relationship.