Obsessive-compulsive behavior was studied in a cohort of N=570 subjects who had been assessed at three times between adolescence and young adulthood. Based on the Youth Self-Report (YSR) and the Young Adult Self-Report (YASR), the adolescent obsessive-compulsive scale (AOCS) was defined. At each of the three assessments, subjects scoring above the cut-off score of the 90th percentile of the AOCS were identified and compared to the rest of the sample serving as control group. The risk group was clearly more abnormal in both domains of internalizing and externalizing across time. Various psychiatric disorders in young adulthood were predicted by the AOCS. However, concomitant general psychopathology also contributed strongly to the prediction. Parent and youth agreement on group membership was rather low. Stability of group assignment across time was significantly increased. The AOCS is a promising instrument both for epidemiological and clinical studies. Its content and predictive validity deserves further studies.