Training and technical assistance programs for autism spectrum disorders (ASD) have emerged in many states as educators, administrators, and institutions of higher education attempt to address the increasing needs for enhancing the knowledge and skills of educators and disseminating the ever-growing knowledge of educational practices. This report provides data from an evaluation study of a professional development effort conducted by a state-sponsored autism spectrum disorders network. Results documented the positive impact of an 18-month, mentored professional development experience for school-based professionals throughout the state. Surveys of trainees' knowledge before and after training indicated shifts in their confidence, from basic knowledge of ASD characteristics and practices to confidence in their ability to implement ASD-related practices. In addition, mentors documented increased use of ASD practices in trainees' classrooms using a checklist of ASD evidence-based practices. (Contains 3 tables.)