Effective continuing medical education (CME) about substance use disorders and treatment can improve physicians' knowledge of the topic and confidence in intervening, which may lead to positive outcomes for patients. With funding from the NIDA and the NIAAA, we have developed and evaluated two Internet-based substance abuse CME programs: one program featuring 12 courses about opioid dependence and buprenorphine treatment (BuprenorphineCME.com), and the other featuring five courses about alcohol abuse and treatment (AlcoholCME.com). Approximately 2000 participants viewed online courses over the past two years and completed a knowledge test, a satisfaction survey, and a self-efficacy, attitude, and intended behavior questionnaire. Preliminary analysis of this data indicates that the educational experience has a statistically significant impact on self-efficacy, attitude, and intended behavior. Also, results show that the CME courses improve knowledge of the topic and that satisfaction with the courses is consistently high (as of 9/15/05, the overall mean satisfaction rating for courses on both sites was 4.5/5.0). An additional upcoming analysis will examine the impact of each entire program on the outcome measures; we will report these findings during the conference presentation. This type of comprehensive evaluation is novel in the world of online CME. We are optimistic that this research will yield useful information about the most effective approach for educating health professionals about substance abuse.