High reinforcement from sedentary behaviors (SB) as measured in laboratory settings is associated with overweight and obesity among small samples of children and adults. However, the utility of survey-based measures of reinforcement among adults remain understudied. The purpose of the current study is to examine associations of reinforcement of SB in real-world environments and weight status using survey measures in a larger sample of adults. Participants were 348 healthy adults (52.9% male) from the United States between the ages 21 and 55 years old, who completed an online mTurk survey. Assessments included measures on Body Mass Index (BMI) and reinforcement (R; frequency * enjoyment) from 10 different active (A) and sedentary (S) activities. Relative reinforcement of sedentary activities was calculated as the ratio: RR = RS / (RA+RS). Controlling for age, sex, and income, four linear regression models were conducted to examine RS, RA, and RRS separately and combined as predictors of BMI. RS and RRS were positively related to BMI (p<.05), and RA was negatively related to BMI (p<.001). Interestingly, when all variables were included in one model, only RS significantly predicted BMI (p< .05). Findings suggest that reinforcement from sedentary behaviors may be a stronger predictor of BMI than reinforcement from active behaviors and reinforcement of sedentary behaviors relative to active behaviors. Adults with high BMI may need alternative activities to compete with SB. Future research should examine healthy alternatives to SB and ways to increase reinforcement from physical activity over sedentary behaviors.