Many schizophrenic patients have comorbid obsessive-compulsive syndromes (OCS) frequently associated with antiserotonergic second-generation antipsychotics such as clozapine and olanzapine. Whereas cognitive behavioral therapy and antiobsessive antidepressants brought up inconsistent results, pharmacological add-on strategies were able to alleviate OCS. One suggestive agent for antiobsessive add-on treatment is aripiprazole, a partial agonist at dopamine and serotonin receptors. Here, we summarize the course of a patient with paranoid schizophrenia. She developed OCS during long-term treatment with olanzapine at 20 mg/d over a period of 10 years. Baseline assessment showed severe obsessions (Yale Brown Obsessive Compulsive Scale (YBOCS) subscale score : 13) and compulsions (YBOCS subscale score : 10), whereas the psychotic syndrome was compensated (Positive and Negative Syndrome Scale, 11/17/28). The combination with aripiprazole (15 mg/) over a period of 12 weeks resulted in a marked improvement of OCS (YBOCS, 8/3) and some further improvement of the psychotic symptoms (Positive and Negative Syndrome Scale, 9/13/27). This observation points toward an antiobsessive potency of aripiprazole in combination with olanzapine, quite similar to approaches involving clozapine. Hence, the proposed strategy should be further evaluated in prospective controlled trials.