The prevalence of tobacco use among adolescents is increasing, and the most common source of tobacco products for persons aged < 18 years (minors) is retail stores. In 1991, an estimated 29.6 million packs of cigarettes were sold illegally to minors in California, and an estimated 255 million packs were sold illegally to minors nationwide. Federal law (i.e., the Synar Amendment) enacted in July 1992 requires all states that receive federal funds for prevention and treatment of substance abuse to have and enforce laws prohibiting the sale or distribution of tobacco to minors, conduct annual statewide inspections of over-the-counter tobacco outlets and vending machines to assess the statewide rate of illegal tobacco sales to minors, and develop a plan to decrease the illegal sales rate to < or = to 20% over several years. On September 28, 1994, California enacted the Stop Tobacco Access to Kids Enforcement (STAKE) Act, which requires that 1) tobacco retailers (i.e., vendors) post warning signs at each point of purchase and check the identification of persons who appear aged < or = to 18 years; 2) the California Department of Health Services (CDHS) develop a statewide enforcement program and establish a toll-free telephone number for reporting observed illegal tobacco sales to minors and 3) CDHS annually assess and report the rate of illegal sales of tobacco products to minors. This report describes the retailer education and enforcement program and summarizes the results of the first two annual assessments (Youth Tobacco Purchase Surveys [YTPSs]). The findings indicate that, from August-September 1995 to June-July 1996, among over-the-counter tobacco outlets the percentage of retailers who asked for age identification increased substantially, the percentage of stores displaying warning signs on age restrictions increased, and the percentage of retailers willing to sell tobacco products to minors decreased.