The quality of the child care environment and caregiver practices can potentially have significant, lasting impact on children's social development. This study involves the development and a smallscale efficacy trial of the Carescapes program, a video-based training program that focuses on promoting positive social development in young children attending family child care. Fifty-seven caregivers who provided child care in their homes were randomly assigned to immediate intervention or waitlist control groups. Random coefficients analyses showed significant increased use of effective behavior management practices and decreased overall children's problem behavior for the intervention group. A mediation model demonstrated that increases in effective behavior management practices were associated with decreases in problem behavior. A medium intervention effect was found for caregiver's monitoring and a small effect for use of positive attention. These effects declined 5 months following the intervention. Implications for future efficacy and effectiveness studies in family child care settings that involve strategies to facilitate maintenance are discussed.Children experience the greatest rate of development during the first 5 years of their lives, and besides the family environment, child care is the setting in which this growth predominately occurs (Shonkoff & Phillips, 2000). Child care is typically the first experience young children will have with a group of other young children, and thus plausibly can facilitate positive interactions and the formation of positive relationships among children, as well as the development of socially skilled behavior in young children. Evidence supports positive influence of child care quality on social outcomes (Loeb, Fuller, Kagan, & Carrol, 2004; NICHD Early Child Care Research Network, 2001;Peisner-Feinberg & Burchinal, 1997;Phillips, McCartney, & Scarr, 1987). Yet the NICHD large-scale study of Early Child Care and Youth Development brings into question whether child care quality has a lasting positive influence on children's social development (Belsky et al., 2007; NICHD Early Child Care Research Network, 2003, 2004. Differential findings likely depend on the child's age when the care is provided, the way in which child care quality is defined, and what social outcomes are assessed.Much less is known about the extent to which the quality of care in family child care settings influences children's social development. In family child care settings, the care of children is Direct all correspondence and send offprints to: Julie C. Rusby, Ph.D., Research Scientist, Oregon Research Institute, 1715 Franklin Blvd., Eugene, OR 97403-1983, 541-484-2123; fax 541-484-1108, e-mail: juliecr@ori.org. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof bef...