This manual presents for the first time a purely cognitive approach to treating obsessive-compulsive disorder (OCD). This approach avoids the highly distressing exposure component of exposure and response prevention therapy (ERP) that is commonly used to treat the symptoms of OCD. Not only does this cognitive therapy (CT) approach open up the option of psychotherapy to those OCD sufferers who resist exposure-based therapy, it also holds great promise for treating OCD sufferers with mental rituals as well as those who struggle concurrently with depression, anxiety, and other symptoms. The strategies described in this book focus intensively on the intrusive thoughts that can trigger negative beliefs and drive compulsive behaviors. The manual begins with a brief review of current facts about OCD. Then it describes how cognitive therapy can be applied to OCD. The several treatment modules that follow outline a brief three-to-four session approach therapists can use to help clients make real progress on their OCD beliefs and behavioral symptoms. Each module is complemented by a series of client worksheets and handouts.