The article presents the Polish version of the Autism Diagnostic Observation Schedule-Generic (ADOS), which together with the Autism Diagnostic Interview - Revised (ADI-R) is cited as the gold standard for the diagnosis of autism. The ADOS is a standardised, semi-structured observation protocol appropriate for children and adults of differing age and language levels. It is linked to ICD-10 and DSM-IV-TR criteria. The ADOS consists of four modules, ranging from Module 1 for nonverbal individuals to Module 4 for verbally fluent adults. The adequate inter-rater reliability for items has been established. The protocol has high discriminant validity and distinguishes children with pervasive developmental disorders from children, who are outside of the spectrum. Although it does not enable to distinguish individuals with pervasive developmental disorder, unspecified from individuals with childhood autism. The paper presents subsequent steps of the translation process of the original version into Polish, as well as a chosen adaptation strategy of the Polish version. The ADOS is a very useful tool both for clinical diagnosis and for the scientific purpose diagnosis. In this last case it is extremely important to use a standardised method. Until now, there was no standardised diagnostic tool for autism in Poland.