Children of working parents, spend, on average, 27 of their waking hours a week in a child care setting. More than 75% of single- and two-parent families rely on non-parental care for their children. The aim of this project was to examine the relationship between the physical and social environment and physical activity levels of children in the Family Child Care context. Participants were 65 children (male = 33, female = 32) from 23 family child care homes. Children's ages ranged from 3.0 years to 5.9 years (M = 4.0, SD = 0.9). Physical activity levels were assessed using the Behaviors of Eating and Activity for Children's Health: Evaluation System (BEACHES) and Actical accelerometers. Affordances in the environment were assessed using the Affordances in the Home Environment for Gross Motor Development (AHEMD) questionnaire. BEACHES and AHEMD were used to describe outdoor play time activity, interactions between the care providers and children, and the nature of the environment. Analysis of the accelerometer data showed that children spent an average of 7.21 hours per day in care (SD = 0.97 hours). Of that time, 3.37 hours (SD = 0.85) per day (46.7%) was spent in sedentary activity (less than 200 counts per minute) and 12.61 minutes (SD = 6.54) was spent in moderate-vigorous physical activity (MVPA; ≥ 2860 counts per minute). Intraclass correlation coefficients revealed there was no association between affordances (toys, space to play) in the environment and MVPA; however during outdoor play time, prompting of physical activity behavior by other children and care providers was significantly and positively associated with chidren's MVPA and vigorous physical activity (r = .441 and r = .458; respectively). These data reveal that children spent very little time per day in moderate or higher levels of physical activity during child care and a large proportion of the day was spent in sedentary activity. Raising levels of moderate-vigorous physical activity in family child care is critical in light of increasing levels of overweight and obesity among children. The association between positive behavior prompts and physical activity is encouraging; however prospective investigation of the relationship between prompting and physical activity participation is needed in this context. This research was funded by a Canadian Institutes of Health Research Obesity and Healthy Body Weight Initiative-Childhood Obesity Pilot Project Grant.Keyword(s): early childhood, exercise/fitness/physical activity, health promotion