Accumulating studies are documenting specific motivational variables that, when combined into a naturalistic teaching paradigm, can positively influence the effectiveness of interventions for children with autism spectrum disorder (ASD). The purpose of this study was to compare two applied behavior analysis (ABA) intervention procedures, a naturalistic approach, pivotal response treatment (PRT) with a structured ABA approach in a school setting. A randomized clinical trial design using two groups of children, matched according to age, sex and mean length of utterance was used to compare the interventions. The data showed that the PRT approach was significantly more effective in improving targeted and untargeted areas after 3 months of intervention. The results are discussed in terms of variables that produce more rapid improvements in communication for children with ASD.