Recent findings from rodent studies with chronic administration of antipsychotic drugs have indicated the role of neural nitric oxide synthase (NOS1) on the susceptibility of tardive dyskinesia (TD). In the present study, the association between a 3'-untranslated region C267T (3'-UTR C267T) polymorphism of the NOS1 gene and TD as well as TD severity was investigated in 251 Chinese schizophrenic patients with long-term antipsychotic treatment (TD: 128, non-TD: 123). After adjusting the effects of confounding factors, there was no significant association between NOS1 3'-UTR C276T genotypes and TD occurrence (p=0.758). With in the TD group, we could not discover a significant correlation between NOS1 3'-UTR C276T genotypes and the scores of abnormal involuntary movement scale (AIMS) (p=0.219 and 0.774). We concluded that the NOS1 3'-UTR C276T polymorphism might not play a major role in the susceptibility of TD development, or on the severity of TD.