OBJECTIVE The purpose of this study was to examine whether baseline sleep duration predicts weight loss outcomes in a randomized controlled trial examining a behavioral weight loss (BWL) intervention among overweight and obese (OW/OB) women with urinary incontinence; and whether participation in the BWL intervention is associated with changes in sleep duration. METHODS Longitudinal, clinical intervention study of a 6-month BWL program. METHODS Three hundred sixteen OW/OB women, with urinary incontinence (age: 30-81 years, body mass index (BMI; 25-50 kg m(-2)) enrolled from July 2004-April 2006. METHODS Measured height and weight, self-report measures of demographics, sleep and physical activity. RESULTS Neither self-reported total sleep time (TST) nor time in bed (TIB) at baseline significantly predicted weight loss outcomes among OW/OB women in a BWL treatment. BWL treatment was successful regardless of how much subjects reported sleeping at baseline, with an average weight loss of 8.19 kg for OW/OB women receiving BWL treatment, versus a weight loss of 1.44 kg in the control condition. Similarly, changes in weight, BMI and incontinence episodes did not significantly predict changes in sleep duration or TIB across the treatment period. CONCLUSIONS Although epidemiological and cross-sectional studies support a relationship between short sleep and increased BMI, the present study found no significant relationship between TST or TIB and weight loss for OW/OB women participating in a BWL treatment.