To investigate the effect of yoga on negative affect (an eating disorders risk factor), 38 individuals in a residential eating disorder treatment program were randomized to a control or yoga intervention: 1 hour of yoga before dinner for 5 days. Negative affect was assessed pre- and post-meal. Mixed-effects models compared negative affect between groups during the intervention period. Yoga significantly reduced pre-meal negative affect compared to treatment as usual; however, the effect was attenuated post-meal. Many eating disorders programs incorporate yoga into treatment. This preliminary evidence sets the stage for larger studies examining yoga and eating disorder treatment and prevention.