Though it has been known for a long time, due to the fact that the controlled studies are limited and the disorder is uncommon, case reports have been important supporting the data of the treatments. In general, depending on whether the patient used drug before and considering the effects and side effects of the drugs the first choice in the treatment is antipsychotic drugs. New atypical antipsychotic agents are preferred for their relatively less side effects and higher drug adaptation. We aimed to report a case of delusional disorder (jealous type) which did not respond to different atypical antipsychotic agents previously but shows a prognostic improvement by aripiprazole of 30mg/day. Aripiprazole may be an effective option for the treatment of delusional disorder, with few side effects, high drug compliance and efficacy.