Autism spectrum disorder (ASD) is a disorder with high levels of co-morbidities. The Developmental, Dimensional and Diagnostic Interview (3Di) is a relatively new instrument designed to provide dimensional as well as categorical assessment of autistic behaviours among children with normal intelligence. Its sound psychometric properties and relatively short administration time make it a versatile instrument. The 3Di was translated into Chinese (Cantonese) and its applicability among 194 clinic children was examined. Results found excellent reliability and validity, and achieved a sensitivity of 95% and specificity of 77%. It was able to capture the diagnosis of ASD among children presenting with attention deficit hyperactivity disorder. However, although the disorder of ASD is considered universal, the use of a western instrument in a Chinese context should also take note of cultural influences that may impact on the manifestation of its symptoms.