Background: Humor and laughter are positively associated with psychological as well as with physical well-being. As there is little research examining to what extent patients suffering from chronic pain could benefit from a humor intervention, the goal of this study was to develop a pain-specific humor training and to evaluate its feasibility and effectiveness as component of regular, multimodal pain therapy. Patients and Methods: Patients from inpatient treatment groups for chronic pain in a German hospital were randomly assigned to the training group (final n = 62) and the control group (final n = 65). The training consisted of four sessions that were implemented in the usual therapy throughout two weeks. Outcomes were divided into primary (perceived current pain intensity and depression) and secondary ones (quality of life impairment by pain, cheerfulness, and self-enhancing humor) and were assessed prior to and after intervention. Results: Results showed improvements in all outcomes for both groups. For primary outcomes, a trend for a greater reduction in current pain intensity was found for the training group compared to the control group (p = 0.060, eta(2)(p) = 0.02), as well as, for secondary outcomes, a trend for greater reduction of quality of life impairment by pain (p = 0.079, eta(2)(p) = 0.02) and a trend for greater increase in self-enhancing humor (p = 0.086, eta(2)(p) = 0.02). Depression and cheerfulness remained unaffected. Feedback indicated feasibility of the training within multimodal therapy, showing overall acceptance as well as providing specific suggestions for improvement. Conclusion: As the first study evaluating a specific humor training for patients with chronic pain within a randomized controlled trial, its results are promising regarding an additional contribution that humor interventions can make towards multimodal pain therapy.