According to the 2006 National Survey on Drug Use and Health (NSDUH), 10.6 percent of adolescents aged 12 to 17 drank alcohol for the first time in the past year, and 5.8 percent used an illicit drug for the first time. According to the 2006 NSDUH, more than 8 million adolescents aged 12 to 17 drank alcohol in the past year, nearly 5 million used an illicit drug, and more than 4 million smoked cigarettes. The Treatment Episode Data Set (TEDS) reported that in 2005 there were 142,646 admissions for adolescents aged 12 to 17 to substance abuse treatment programs. TEDS also indicates that on an average day in 2005, adolescent admissions to treatment presented with the following substances as the primary substance of abuse: marijuana (255), alcohol (72), stimulants (24), cocaine (10), opiates (7) and other drugs (7). Referrals to substance abuse treatment came from the criminal justice system, self-referral or referrals from individuals, schools, community organizations, alcohol or drug treatment providers, and other health are providers. Information from the National Survey of Substance Abuse Treatment Services (N-SSATS) reported how many active clients under the age of 18 received outpatient treatment (76,240), non-hospital residential treatment (10,313) and in-hospital inpatient treatment (1,058). This issue of the Office of Applied Studies (OAS) presents facts about adolescent substance use, including initiation, and receipt of treatment for substance use “on an average day.” Data presented in this report from the 2006 NSDUH and the 2005 TEDS are for adolescents aged 12 to 17; data presented from the 2005 N-SSATS are for youth under 18.