This article provides an overview of the etiology, epidemiology, and first-line treatment options for obsessive-compulsive disorder (OCD). The subject of treatment-resistant and treatment-refractory OCD is the discussed, including a definition of these often-debated terms, and the latest treatment options delineated. This includes a review of the latest research concerning the pharmacological agents that have been studied as monotherapy or augmenting agents for the treatment of OCD, the use of experimental medications and procedures, treatment with reversible, minimally invasive procedure, such as vagal nerve stimulation and transcranial magnetic stimulation, invasive but the potentially reversible deep brain stimulation, and irreversible lesioning with ablative psychosurgery. A discussion of the role of psychotherapy in the treatment of OCD is also included.