Behavioral activation (BA) and acceptance and commitment therapy (ACT) are considered particularly useful treatments when dealing with emotional problems of cancer survivors. The efficacy of these two treatments, applied on a group basis, were evaluated and compared. An analysis was carried out of pre-post treatment changes in the emotional state and patterns of activation/avoidance of 52 cancer patients, with anxiety and/or depression, randomly assigned to three groups (BA/ACT/waiting list control). Both therapies were superior to no treatment in all the variables evaluated. Significant differences were found between the two treatments in favor of ACT in social impairment and avoidance/rumination. BA and ACT, applied on a group basis, are efficacious in the treatment of those emotional difficulties most prevalent in cancer survivors. Results suggest that activation and avoidance are the mechanisms responsible for the changes.