Background and aims: Compulsive sexual behavior disorder (CSBD) has been included as an impulse control disorder in the International Classification of Diseases (ICD-11). However, the neurobiological mechanisms underlying CSBD remain largely unknown, and given previous indications of addiction-like mechanisms at play, the aim of the present study was to investigate if CSBD is associated with structural brain differences in regions involved in reward processing. Methods: We analyzed structural MRI data of 22 male CSBD patients (mean 5 38.7 years, SD 5 11.7) and 20 matched healthy controls (HC; mean 5 37.6 years, SD 5 8.5). Main outcome measures were regional cortical thickness and surface area. We also tested for case-control differences in subcortical structures and the effects of demographic and clinical variables, such as CSBD symptom severity, on neuroimaging outcomes. Moreover, we explored case-control differences in regions outside our hypothesis including white matter. Results: CSBD patients had significantly lower cortical surface area in right posterior cingulate cortex than HC. We found negative correlations between right posterior cingulate area and CSBD symptoms scores. There were no group differences in subcortical volume. Conclusions: Our findings suggest that CSBD is associated with structural brain differences, which contributes to a better understanding of CSBD and encourages further clarifications of the neurobiological mechanisms underlying the disorder.  Kulcsszavak: compulsive sexual behavior, hypersexual disorder, neuroimaging, surface area, reward, brain structure