Objectives: Data indicate that some developmentally and behaviorally based early intervention programs can lead to a range of improvements in children with autism spectrum disorder. However, many such programs call for a fairly intensive amount of intervention. The objective of this preliminary study was to evaluate the effectiveness of a low-intensity therapist delivered intervention for young children with autism spectrum disorder. Methods: The study evaluated the outcomes of 3 hours per week of therapist-delivered early start Denver model intervention (ESDM) over a 12-week period for four preschool-aged boys with autism spectrum disorder. The effects of intervention on communication, imitation, and engagement were evaluated using a non-concurrent multiple probe across participants design. Results: Following the intervention, all four children showed increases in imitation, engagement, and either functional utterances or intentional vocalizations. These results were maintained after 4 weeks and mostly generalized to each child's mother. Conclusion: These preliminary results suggest that low-intensity therapist delivered ESDM intervention may be of some benefit to children with autism spectrum disorder.