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.