Antipsychotic drugs exert both therapeutic and adverse effects through dopamine D2 receptor (DRD2) antagonism. Genetic variants of this receptor may be responsible for individual variations in neuroleptic response and may therefore be useful in predicting response. In this study we evaluated the role of six polymorphisms of the DRD2 gene in 125 risperidone-treated Chinese schizophrenia patients following the hypothesis that variation in the DRD2 gene could affect drug response. Response was categorized as a change of >40% on the Brief Psychiatric Rating Scale (BPRS). Our results show that genotyping A-241G may help to predict the efficacy of risperidone treatment on the basis that patients with the A allele showed greater improvement than those with the G allele on the overall BPRS (chi2=7.19, p=0.007, p=0.031 after correction by the program SNPSpD), while other polymorphisms, including -141C Ins/Del, TaqIB, rs1076562, T939C and TaqIA, did not show any association with the response to risperidone. These data suggest that the DRD2 A-241G polymorphism or, alternatively, another genetic variation that is in linkage disequilibrium, may influence response to risperidone in schizophrenia patients.