The number of children diagnosed with Autism Spectrum Disorder (ASD) is growing and related communication problems affect all spheres of their lives. There is evidence that script fading procedures are effective in teaching conversational skills to children with autism aged 2 to 15 years, but there is little evidence of its effectiveness for adolescents and young adults (aged 15 to 23 years of age). The first aim of the present study is to demonstrate that script fading can be applied with success to adolescents and young adults with autism. The second aim of the study is to establish internal validity for a new data collection procedure that can be easily and practically implemented in applied setting, particularly for intensive interventions. Findings showed that adolescents and young adult with autism can benefit from script fading procedure as do younger participants and that the new data collection method is useful to evidence this process.