Physical activity (PA) and sedentary behavior (SB) have been associated with total and abdominal obesity. There are different levels and types of PA and SB. The current study aims to discover which levels and types of PA and SB are associated with total and abdominal obesity. Most studies on obesity use body mass index (BMI) and waist circumference (WC) as measures of total and abdominal fatness, respectively. However, BMI does not differentiate between fat and fat-free mass and WC is actually a measure of total body fat that is influenced by abdominal fat. The current study uses dual energy x-ray absorptiometry to measure total and abdominal fat accurately and precisely, which will add to the literature on levels and types of PA and SB and their associations with total and abdominal obesity. The results may inform future interventions that aim to alter body composition by highlighting the specific levels and types of PA and SB that are most strongly associated with obesity. Participants were 298 overweight or obese men and women between the ages of 21 and 60. Levels of activity (e.g., SB, light PA, and moderate to vigorous PA) were assessed by accelerometer. Types of PA (e.g., leisure, occupational, and transportation) and types of SB (e.g., watching TV, leisure, occupational, and total) were obtained by self-report questionnaires. Total body fat and abdominal fat were measured by dual-energy x-ray absorptiometry. Multiple linear regressions were used to examine the relationships between levels of activity, types of PA, and types of SB with total and abdominal fat while controlling for gender, age, and total body fat. We found that moderate to vigorous PA was negatively associated with total and abdominal fat. However, we were unable to identify which types of PA were significantly associated with total and abdominal fat. In addition, types of SB were not significantly associated with total or abdominal fat. Thus, interventions for reducing obesity should promote moderate to vigorous levels of activity. More research is needed on which types of PA should be encouraged and whether or not SB should be discouraged.