Childhood autism belongs to pervasive developmental disorders. and is characterised by qualitative abnormalities in reciprocal social interactions, communication, and by restricted, repetitive interests and behaviours. Until now there was no standardised tool for a diagnosis of autism in Poland. The paper presents the Polish version of the Autism Diagnostic Interview Revised (ADI-R), which is the gold standard for the diagnosis of autism in Europe, United States and Australia. It describes the translation process and adaptation of the original version into Polish, as well as differences between the two versions. ADT-R is a complex, standardised, semi-structured investigator-based interview for parent or caregiver of person with autism, linked to ICD-10 and DSM-IV-TR criteria and appropriate for both adults and children, who have the minimum mental age of 24 months. Moreover ADI-R consists of beside diagnostic algorithms, the current behaviour algorithms, which enable to assess and compare various levels of functioning during planning and implementation of treatment and therapy. ADI-R is also a very useful tool in the diagnosis for scientific purposes due to its standardisation.