Background : In spite of the worldwide relevance of obsessive-compulsive disorder Ed-highlight : Unclear. Perhaps consider changing word choice. (OCD), there are considerable differences in prevalence, sex ratio, comorbidity patterns, and sociodemographic correlates. Data on subclinical OCD have been sparse to date. Methods : Data stemmed from the Korea Epidemiologic Catchment Area (KECA) study which had been carried out from April to December 2001. Korean versions of DSM-IV adapted Composite International Diagnostic Interview were administered to a representative sample of 6275 persons aged 18-64 living in the community. DSM-IV based criteria for subclinical OCD were applied. Results : The lifetime prevalence rates for OCD and subclinical OCD were 0.8% and 6.6%, respectively. In both OCD and subclinical OCD, the rates for males and females were not statistically different. OCD was demonstrated to be associated with depressive disorder, bipolar disorder, social phobia, generalized anxiety disorder, and alcohol and nicotine dependence. Additionally, subclinical OCD was associated with posttraumatic stress and somatoform disorders. Comorbidity rates in subclinical OCD were lower than those in OCD. Conclusions : The lifetime prevalence rate for OCD was less than 1% in the Korean general population. Age distribution and comorbidity patterns suggest that subclinical OCD represents a broad and heterogeneous syndrome and not simply a milder form of OCD.