The purpose of this study was to examine the potential improvements in eating self-efficacy, eating behavior and other psychological factors in obese subjects participating in a weight management program. The participants in this study consisted of 96 persons (76 women and 20 men) who were attending the first session of a commercially run 20-week treatment program for weight reduction. Self-efficacy in relation to eating was assessed by the Weight Efficacy Lifestyle Questionnaire. The participants also completed the Three Factor Eating Questionnaire (TFEQ), Rosenberg Self-esteem Scale, Social Physique Anxiety Scale, State Trait Anxiety Inventory and Body Parts Satisfaction Scale prior to weight management program and again 20 weeks after the program. High self-efficacy score was significantly associated with high weight loss among all participants. Also, high negative emotions and physical discomfort scores were significantly associated with high weight loss among all participants. Results indicated that there was a significant decrease in the TFEQ hunger and disinhibition scores during the study. As a conclusion, our findings suggest that the role of self-efficacy has an important role in obesity treatment regarding to weight control behavior. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.