Instruments for measuring learned expectations for reinforcement from eating and from dieting and thinness were constructed and validated. Five eating reinforcement expectancies and 1 dieting–thinness reinforcement expectancy were identified and their factor structure replicated on an independent sample. The expectancy that dieting and thinness lead to overgeneralized self-improvement characterized bulimia nervosa and anorexia nervosa patients and correlated with dieting behavior in a general sample. Expectancies for negative reinforcement from eating (e.g., eating helps manage negative affect) characterized bulimic but not anorexic individuals and were correlated with indexes of restraint plus disinhibition in a general sample. Positive reinforcement expectancies (e.g., eating is pleasurable and rewarding) were unrelated to disinhibited eating, but anorexic patients expected significantly less positive reinforcement from eating than did bulimic patients or controls.