This study assessed the relationship between self-perceived clinical and social needs and aggressive behavior in outpatients with schizophrenia. A total of 895 outpatients with schizophrenia were enrolled. The presence of aggressive episodes was assessed using the Modified Overt Aggression Scale. Self-perceived needs were assessed using the Camberwell Assessment of Need in six areas of needs (food, household skills, self-care, daytime activities, psychotic symptoms, satisfaction with treatment, and company). The most common areas of needs were "psychotic symptoms" (81.6%), "daytime activities" (60.6%), and "household skills" (57.5%). More needs were expressed by patients who had more severe illnesses (p < 0.001) and more aggressive behavior (p < 0.001). Multivariate analysis showed that, in schizophrenia outpatients, self-perceived needs were associated with aggressive behavior (adjusted odds ratio, 11.43; 95% confidence interval, 5.11 to 25.56). Appropriate compliance with antipsychotic treatment was related with lower aggressive behavior (p < 0.001).