Obesity is a serious health problem among women across the life span. Although people can become obese at any age, there is a large proportion of older women who have been obese since childhood. The purpose of this study was to determine whether postmenopausal women with an early versus late onset of obesity manifested differences in body habitus, eating behaviors, and mood. One hundred thirty-five postmenopausal women with obesity responded to self-report questionnaires on weight history, weight loss and maintenance expectancy, eating behaviors, and mood. Women with an early onset of obesity had a significantly higher body mass index (BMI), waist circumference, and highest attained adult body weight than women with a late onset of obesity. They had attempted a significantly larger number of diets and had lost more weight on any single diet. The groups also differed significantly on binge eating and overeating in response to negative affect. There was a tendency for women with an early onset to have more depressive and anxious symptoms. Postmenopausal women with an early onset of obesity differed physiologically and psychologically from those with a late onset. Tailoring dietary and behavioral interventions to profiles of postmenopausal women based on onset of obesity may improve the overall efficacy of weight loss programs.