This study investigated the demographic and clinical factors that influence treatment status in family members with obsessive-compulsive disorder (OCD). Six hundred and two subjects from the OCD Collaborative Genetics Study were interviewed using the Structured Clinical Interview for DSM-IV (SCID) to diagnose Axis I disorders, and the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) for assessment of OCD symptoms. The demographic and clinical data were compared between subjects who had received treatment and those who had not. A precipitous onset of symptoms, severe illness, multiple obsessions and compulsions, and co-morbid affective disorders were all positively associated with receiving treatment. Older age and the presence of obsessive compulsive personality disorder (OCPD) or OCPD traits were negatively associated with treatment. Gender and age at onset of symptoms did not predict treatment history. The mean duration from onset of symptoms to receiving treatment was 13.87SD 11.9 years, but there was a direct relationship between current age and time to treatment, with younger subjects receiving treatment sooner. Clinical factors are predominant in predicting treatment status in family members with OCD. Although the mean duration from onset of symptoms to treatment was long, younger family members appear to receive treatment sooner. Depression and Anxiety 25:218-224, 2008.