There is no doubt that dopamine plays a critical role in the etiopathogenesis of schizophrenia. However, there appeared some limitations in explaining the complex phenomena of schizophrenia. Recent research data suggest that dysfunction in serotonergic system may be involved Before the dopamine hypothesis of schizophrenia became established, the interest in serotonin(5-ydroxytryptamine, 5-HT) as an etiological substrate of this illness occurred. Recently the importance and extent of 5-HT's involvement in the pathophysiology and mechanism of action of antipsychotic drug is actively investigated. In recent years, therapeutic success of clozapine and risperidones has increased attention on the interaction between the 5-HT and dopamine systems in schizophrenia. This led to the serotonin-dopamine for antipsychotic. The authors review the evidence for the role of 5-HT in schizophrenia and serotonin-dopamine interaction.