There is a debate concerning comorbid Asperger's syndrome and schizophrenia which eventually influences patient management. Comorbid schizophrenia with Asperger's syndrome cases have been mostly treated with risperidone. A 26 year old man with insomnia, irritability, aggressive behaviors, delusions (reference, persecutory and thought broadcasting), auditory hallucinations, and loss of pleasure in his interests for two years was admitted to our inpatient unit. His initial assessment, according to the positive and negative syndrome scale (PANSS) was 109 points and clozapine 12.5mg/day was initiated and titrated up to 200mg/day. In his childhood he had been diagnosed with Asperger's Syndrome because of stereotypic behaviors and odd interests. He was discharged with a PANSS score of 65 points at week seven. Clozapine might be a safe and effective treatment choice in patients with co-morbid Asperger's syndrome and schizophrenia.