The aim of this study was to confirm prior results of brain-imaging studies on obsessive-compulsive disorder (OCD) in a sample of Turkish patients, as a cross-cultural study. Tc-99m HMPAO brain perfusion SPECT imaging was performed in nine drug-free OCD patients without depression and six controls. The patients' Hamilton Depression Rating Scale scores were <16. The severity of obsessive-compulsive symptoms was rated with the Yale-Brown Obsessive-Compulsive Rating Scale (YBOCS). Quantitative evaluation of regional cerebral blood flow revealed that right thalamus, left frontotemporal cortex and bilateral orbitofrontal cortex showed significant hyperperfusion in patients with OCD compared with controls. YBOCS scores did not show any correlation with hyperperfusion in regional cerebral blood flow in these areas. Results of this cross-cultural study may support orbitofrontal and thalamic dysfunction in OCD in a sample of Turkish patients.