There are a number of studies examining clinical and comorbidity profiles among patients with treatment-resistant obsessivecompulsive disorder (TR-OCD); however, there have been far fewer investigations of neurocognitive function among such patients. Five patients with treatment-refractory obsessive-compulsive symptoms underwent neurocognitive and clinical/ personality testing. A number of TR-OCD patients met diagnostic criteria for major axis I disorders (particularly mood and anxiety disorders) as well as clusters A, B, and C personality disorders. TR-OCD patients demonstrated significant performance deficits on neurocognitive tests of visuospatial working memory, visuoconstructive ability, and executive control as well as one test of processing speed, but not a second, relative to healthy normative controls. TR-OCD patients and normative controls did not differ significantly on measures of verbal working memory, sequencing, figure copy organization, inhibitory control, and odor identification. In addition, TR-OCD patients were directly compared to five healthy controls evaluated in our laboratory for a separate unpublished study. TR-OCD patients demonstrated significant performance deficits on tests of visuospatial working memory, information processing speed, and executive control, and obtained substantially higher scores on dimensional measures of social anxiety and depressive symptom severity, but not schizotypal personality features. Group differences of tests of verbal working memory, inhibitory control, and additional tests of executive function were not significant. In summary, patients with TR-OCD presented with comorbid axis I conditions (primarily mood and anxiety disorders) and personality disorders. TR-OCD patients demonstrated deficits on some, but not all, tests of working memory and executive control. Neurocognitive test findings lend partial support to the hypothesis that right hemisphere (particularly dorsolateralprefrontal, but not orbitofrontal) dysfunction is associated with TR-OCD, and a number of TR-OCD patients met diagnostic criteria for major axis I disorders (particularly mood and anxiety disorders) as well as cluster A, B, and C personality disorders further complicating treatment. (C) 2016 Published by Elsevier Ltd.