To determine the prevalence of psychiatric disorders among Vietnamese children and adolescents living in Perth, Western Australia. A list of Vietnamese households was drawn from Perth telephone directories. A computer program generated a systematic probability sample of households. All children and adolescents aged 9-17 in these households were invited to participate in the study. Children and their parents were interviewed in their home using the Diagnostic Interview Schedule for Children, version 2.3 (DISC-2.3). The child version (DISC-C) was used for children and the parent version (DISC-P) for adults. The study was conducted between July and December 1997. The prevalence of psychiatric disorders in children and adolescents, based on DISC-C and DISC-P data. Results were based on the 519 children (89.2%) for whom complete data were available. Twenty-three parents (4.4%) reported that their child had one or more disorders on the DISC-P, 82 children (15.8%) reported one or more disorders on the DISC-C, and 18.3% of children were reported to have a disorder on either the DISC-C or the DISC-P. Parent-child concordance on specific diagnoses was very low (0.6%). The great majority of disorders reported were anxiety disorders, especially simple and social phobias. The combined prevalence of psychiatric disorders among Vietnamese children aged 9-17 was similar to that found among children in Western Australia's general population. Vietnamese children in our study were much more likely to report symptoms of a psychiatric disorder than were their parents.