Clinical wisdom and intuition suggest that when treating major depression and/or anxiety disorders, combining two documented efficacious treatments such as antidepressants and psychotherapy would improve outcome. However, the data do not completely support this conclusion. This chapter reviews randomized clinical trials comparing combined pharmacotherapy and psychotherapy with monotherapy for the treatment of major depressive disorder, panic disorder, obsessive-compulsive disorder, posttraumatic stress disorder, generalized anxiety disorder, and social anxiety disorder in adults. Although DSM-V no longer categorizes posttraumatic stress disorder and obsessive-compulsive disorder as anxiety disorders, the authors continue to include them in this chapter.