Classroom conversations about mathematics--math talk--between early care and education providers and young children have been associated with growth in mathematical thinking. However, professional development opportunities to learn about math teaching and learning are limited in many community-based child development centers. New approaches that are less costly and time consuming are needed to support providers in planning and implementing rich math experiences for young children. Professional development activities that are offered within the work site and during work hours may be most feasible for a large percentage of community-based programs. The purpose of this study was to design and test the impact of brief, data-based staff meetings during naptime in child care classrooms on providers' math interactions with their students. Findings indicate that such meetings increase participants' math talk in specific domains and predict growth in children's math abilities 6 months later. The potential of naptime data meetings to enhance math interactions and other areas of professional practice are discussed. Future directions for additional research are recommended. (author abstract)