Among 307 adults with OCD, early onset (age 5-15 years) was more common in men and later onset (age 26-35 years) in women. Early onset was associated with more checking, and late onset with more washing. More women than men had a history of treated depression; 12% of the women but none of the men had a history of anorexia. More women than men were married. Gender-divergent features may reflect differential aetiological factors. Our sample resembled others in the literature in its slight overall female preponderance, low rate of marriage and low fertility, onset mainly before age 35 years, chronicity, and common present and past depression.