Although depression and rumination have been associated with a difficulty ignoring irrelevant negative content, the causal direction of this relationship is unclear. The aim of this study was to train individuals who engage in habitual brooding, a particularly maladaptive subtype of rumination, to inhibit or to attend to negative stimuli. The effects of the training on rumination and depression were examined. Participants were randomly assigned to four sessions of training to inhibit or to attend to negative stimuli or to a sham-training group, in a two-week span. At both pre and post training, participants completed measures of depressive symptoms, rumination and inhibition bias. Compared with individuals in the sham training condition, those who were trained to attend to negative stimuli exhibited a significant decrease in inhibition of irrelevant negative content whereas those who were trained to inhibit negative stimuli, showed a trend toward improved inhibition of irrelevant negative content and a reduction in brooding, but not in depressive symptoms. Our findings suggest that inhibition training may be beneficial for reducing brooding.