There is a long-recognized association between obsessive-compulsive disorder (OCD) and chronic epilepsy, most notably refractory temporal lobe epilepsy (TLE). The literature documents this association with case reports, patient series, and some larger controlled studies that reveal that almost a quarter of patients with TLE exhibit OCD features, which may go unrecognized. Obsession features with ordering, symmetry, exactness, handwashing, and religiosity occur more often in persons with right- or left-sided epileptic foci than in those with idiopathic generalized epilepsies or controls. Neurobiological and social factors suggest abnormalities of the frontal-thalamic-pallidal-striatal-anterior cingulate-frontal circuits stemming from the observation that certain diseases, damage, or surgery along these circuits may produce or, conversely, reduce OCD in TLE. This review explores the literature on case reports, case series, and larger retrospective controlled studies and looks at the associations of epilepsy with OCD. Contemporary speculation on the theoretical neurobiological underpinnings provides some basis on how and where to direct treatment. Invasive deep brain stimulation has triggered recent controversy on newer treatment modalities.