OBJECTIVE: Only scanty information on the prevalence of tardive dyskinesia in Chinese patients has been available. This study was undertaken to examine the prevalence of tardive dyskinesia, tardive dystonia, and respiratory dyskinesia in Chinese psychiatric patients in Hong Kong. METHOD: All inpatients of a mental hospital in Hong Kong, except those in the admission and children's wards, were surveyed with the Abnormal Involuntary Movement Scale, and standard research criteria were used to establish the diagnosis of tardive dyskinesia. In addition, patients were screened for tardive dystonia, according to published criteria, and for respiratory dyskinesia by physical examination and laboratory tests. RESULTS: Among the 917 patients surveyed, the prevalence rates were 9.3% for tardive dyskinesia, 0.4% for tardive dystonia, and 1.2% for respiratory dyskinesia. With multivariate analysis, greater age and a lower current dose of antipsychotic, but not the presence of mood disorder, were factors found to be significantly associated with tardive dyskinesia. CONCLUSIONS: The prevalence rates were much lower than those found in Western studies. This may indicate that there is an ethnic difference in the prevalence of these conditions. Prospective cross-cultural studies are necessary to explore this possibility.