With funding from the National Institute on Drug Abuse, we delivered a Web training program on cognitive behavioral therapy (CBT) to addiction counselors and supervisors in 54 U.S. addiction units and conducted a randomized controlled trial with 127 counselors in 2006–07. Adequate adherence to CBT practice at pre- and post-training was judged from audiotapes of client sessions using an adequacy rating guide of counseling skills. A web-administered questionnaire assessed demographics, prior training, attitudes, and self-report counseling practices. Logistic regression model findings are described with discussion of dissemination of evidence-based practices, study limitations, and future research needs for empirically-supported training programs.