We compared early-onset and late-onset obsessive–compulsive disorder (OCD) patients in terms of demographic and clinical features. One hundred sixteen outpatients whose primary diagnosis was OCD according to DSM-IV diagnostic criteria were recruited. Early-onset (n=50) and late-onset (n=66) OCD groups were compared with respect to demographic variables and scores obtained on various scales. A male gender predominance was found in early-onset OCD group. Symmetry/exactness obsessions, religious obsessions, hoarding/saving obsessions, and hoarding/collecting compulsions also were significantly more frequent in the early-onset group than in the late-onset group. The results may suggest a phenotypic difference between the two groups. Further studies are needed to investigate the differences between early-onset and late-onset OCD groups to examine the hypothesis that early-onset OCD is a distinct subtype of the disorder. © 2005 Wiley-Liss, Inc.