Mindfulness‐Based Stress Reduction (MBSR) is an 8 week course that teaches participants to change their patterns of reacting to stress. To accomplish this goal, participants practice meditation to increase their ability to attend to emotions and develop the ability to attend to their patterns of reactivity. In theory, this awareness will eventually enable participants to reduce their automatic emotional reactions. Our study attempts to directly test the effects of MBSR on attentional control over emotional information. We examined whether MBSR participants altered their involuntary bias to attend to negative emotional information in a behavioral task, in which participants make indoor/outdoor judgments of scenic pictures while attempting to ignore faces that are superimposed over the scenes. When the faces are sad instead of neutral, participants tend to make slower indoor/outdoor responses, even though the faces do not help with the task. We examined whether MBSR would affect the involuntary capture of attention by the sad faces. At the same time, we acquired fMRI images of participant brain activity to understand whether training was affecting the way the emotional information was being processed in the brain. As an experimental control, we compared training effects in the MBSR group against training effects in a relaxation training group, who also had daily practice in relaxation without additional training in controlling attention towards emotion.