This study describes the main social, economic, biological, and demographic characteristics of children and families who participate or have participated in the Children's Pastoral as compared to the overall urban population of Criciúma (Southern Brazil). A population-based cross-sectional study with a probabilistic sample of 2208 children under three years of age was conducted; 16.7% of the mothers confirmed having participated in the Pastoral at any given time, of whom 4.8% were currently participating, while the rest had dropped out. Black children and those over 12 months old or with two or more older siblings participated more frequently in the Pastoral. The main family factors associated with participation were mother's age (over 25), mother not working outside the home, low per capita income, low parental schooling, living in the neighborhood for more than 4 years, and death of sibling before age five. Reasons most often given by mothers for dropping out were migration, lack of time, and interruption of the Pastoral's activities in the neighborhood. The conclusion was that the Pastoral should prioritize the poorest of the poor and adopt measures to reduce drop-out rates.