According to the integrative model of somatoform disorders, illness behavior plays an important role especially in the maintenance of somatic symptoms. Illness behavior can be extremely diverse and subtle in patients with persistent somatic symptoms. At the same time, patients with persistent somatic symptoms are very heterogeneous in terms of their illness behavior—not all known dysfunctional behaviors are necessarily present in all patients. In the four sessions of the fifth module, we focus on those illness behaviors that are most commonly evidenced in patients with persistent somatic symptoms. The four sessions focus on avoidance behaviors, excessive preoccupation with one’s own body and health, sick role behaviors and secondary illness gain, and finally on utilization of medical services.