Obsessive-compulsive disorder is an illness that can cause marked distress and disability. It often goes unrecognized and is undertreated. Primary care physicians should be familiar with the various ways obsessive-compulsive disorder can present and should be able to recognize clues to the presence of obsessions or compulsions. Proper diagnosis and education about the nature of the disorder are important first steps in recovery. Treatment is rarely curative, but patients can have significant improvement in symptoms. Recommended first-line therapy is cognitive behavior therapy with exposure and response prevention or a selective serotonin reuptake inhibitor. The medication doses required for treatment of obsessive-compulsive disorder are often higher than those for other indications, and the length of time to response is typically longer. There are a variety of options for treatment-resistant obsessive-compulsive disorder, including augmentation of a selective serotonin reuptake inhibitor with an atypical antipsychotic. Obsessive-compulsive disorder is a chronic condition with a high rate of relapse. Discontinuation of treatment should be undertaken with caution. Patients should be closely monitored for comorbid depression and suicidal ideation.