Substance abuse is a major public health problem. Medicaid clients are more likely than people with other types of insurance to have chemical dependency problems. As it happens, Medicaid is now a major payer for substance abuse treatment services. Medicaid's share of substance abuse treatment payments nearly doubled from ten percent in 1986. At the moment, Medicaid exceeds the Federal substance abuse block grant program in funding for chemical dependency treatment and is itself exceeded only by state and local payments. This book presents information on Medicaid and its position in providing treatment for those with substance abuse problems.