The therapeutic limitations of mainstay psychopharmacological treatments of obsessive-compulsive disorder (OCD) warrant the clinical testing of further add-on agents to improve patients' clinical symptoms. One such agent might be pregabalin, which has been found efficacious in other anxiety disorders. We report on the findings of a small, 8-week open-label trial of adjunctive pregabalin with a 4-week follow-up in 10 OCD patients resistant or only partial responders to a combination of serotonin reuptake inhibitors with atypical antipsychotics. Adjunctive pregabalin at 225-675 mg/d was well tolerated and led to patients' substantial improvement in their OCD symptoms, as reflected in their scores on the Yale-Brown Obsessive Compulsive Scale. Despite the several limitations of the study, its results suggest that adjunctive pregabalin might be a safe and efficacious new augmentation agent in the treatment of drug-resistant OCD. We hypothesize that pregabalin's mechanism of action in OCD might consist in its inhibition of glutamatergic neurotransmission.