Background- Bariatric surgery candidates' physical activity (PA) level may contribute to the variability of weight loss and body composition changes following bariatric surgery. However there is little research describing the PA of patients undergoing bariatric surgery to inform PA recommendations in preparation for and following surgery. Objectives- Describe PA assessment in the LABS-2 study and report pre-surgery PA level. Examine relationships between objectively determined PA level and 1) BMI and 2) self-reported purposeful exercise. Setting- Six sites in the U.S. Methods- Participants wore an accelerometer and completed a PA diary. Standardized measures of height and weight were obtained. Results- Of 757 participants 20% were sedentary (<5000 steps/day) 34% low active (5000-7499 steps/day) 27% somewhat active (7500-9999 steps/day) 14% active (10000-12499 steps/day) and 6% were highly active (greater than or equal to 12500 steps/day). BMI was inversely related to mean steps/day and mean steps/minute during the most active 30 minutes each day. The most commonly reported activities were walking 44%; gardening 11%; playing with children 10%; and stretching 7%. Self-report of minutes of exercise accounted for 2% of the variance in objectively determined steps. Conclusion- Patients present for bariatric surgery with a wide range of PA levels with almost half categorized as somewhat active or active. BMI is inversely related to total amount and intensity of PA. Few patients report a regular pre-operative exercise regimen suggesting most PA is accumulated from activities of daily living. Patient report of daily minutes of walking or exercise may not be a reliable indication of their PA level. Originally published Surgery for Obesity and Related Diseases Vol. 4 No. 6 Nov-Dec 200