|Both childhood obesity and the number of children in self-care have increased during the past several decades. Child care arrangements for working parents of middle school children can be a complex problem because unsupervised children who ?ang out?with peers after school are more likely to engage in risky behaviors, although unsupervised children at home after school tend to watch more television than their supervised peers. Because children in self-care at home after school tend to engage in more sedentary activities, they may be at greater risk for becoming overweight or obese. The purpose of the present study was to examine the extent to which activity level may mediate a relationship between at-home self-care and childhood obesity. Participants completed a structured activity journal to record daily after-school activities for one week? time. A series of three regression models was estimated to examine the hypothesized relationships among the following variables: time spent unsupervised, activity level, and BMI percentile. The results of these analyses suggested that relationships among these variables do not exist. Additionally, several ancillary analyses were conducted to examine the findings in greater depth. One ancillary analysis compared the responses participants gave about their activities each hour and their subjective ratings of their activity levels. Two independent judges rated the activity level of each participant, and the judges?activity ratings were compared to the participants?activity ratings. A second ancillary analysis examined whether there was a difference in how participants in the different weight classifications perceived their activity level to be. A final analysis compared the participants?weight classification with how healthy the participants?recorded food intake was judged to be. Qualitative observations regarding the reported food intake and activity level were also included to provide additional information regarding factors that may be contributing to the proportion of overweight/obese participants. Results of the ancillary analyses, interpretation of the primary and ancillary analyses, critique of the methodology, and suggestions for future research are addressed.