A summary of the findings include: (1) in the United States, admission rates to substance abuse treatment facilities increased between 1995 and 2005 for marijuana, methamphetamine/amphetamine, and opiates other than heroin; (2) in both 1995 and 2005, methamphetamine/amphetamine admission rates were generally highest in the Pacific and Mountain States; and (3) in both 1995 and 2005, marijuana treatment admission rates were generally highest in the West North Central and Pacific States. Among the six primary substances of abuse that dominate the Treatment Episode Data Set (TEDS), the rates of substance abuse treatment admissions in the United States increased for three (marijuana, methamphetamine/amphetamine, and opiates other than heroin) and decreased for three (alcohol, cocaine, and heroin). This report focuses on trends in admission rates for methamphetamine/amphetamine and marijuana, which have the largest number of admissions among the substances with increased admission rates, thereby having the greatest impact on the treatment system. Tables, figures