Tobacco use is the single most preventable cause of death and disease in our society. Annually, in the United States, tobacco use causes more than 430,000 deaths. Direct medical costs related to smoking total at least $50 billion per year; lost productivity adds another $50 billion. Tobacco use is addictive: nearly 70% of smokers want to quit smoking, but only 2.5% are able to quit permanently each year. Most smokers start smoking as adolescents. One in three teenagers who are regular smokers will eventually die of smoking-related causes. Other tobacco products also have serious health consequences. Use of smokeless tobacco is associated with leukoplakia and oral cancer. There is also strong evidence of causal relationships between regular cigar use and cancers of the lungs, larynx, oral cavity, and esophagus. These consequences are of particular concern because in 1999, 15.3% of U.S. high school students smoked cigars and 6.6% used smokeless tobacco. The risks of tobacco use extend beyond the actual users. Nearly 9 of 10 nonsmoking Americans have been exposed to environmental tobacco smoke (ETS). Exposure to ETS increases nonsmokers' risk for lung cancer and heart disease. Among children, ETS is also associated with serious respiratory problems, including asthma, pneumonia, and bronchitis. In addition, scientific evidence now links ETS with sudden infant death syndrome (SIDS) and low birth weight. Tobacco control programs are designed ultimately to help reduce disease, disability, and death related to tobacco use. To determine the effectiveness of these programs, one must document and measure both their implementation and their effect. Program evaluation is a tool used to assess the implementation and outcomes of a program, to increase a program's efficiency and impact over time, and to demonstrate accountability. This document is a “how to” guide for planning and implementing evaluation activities. The manual reflects the priorities of the Centers for Disease Control and Prevention (CDC), Office on Smoking and Health (OSH), for program monitoring and evaluation. The purpose of this manual is to assist state tobacco control program managers and staff in the planning, design, implementation, and use of practical and increasingly comprehensive evaluations of tobacco control efforts. The strategy presented in this manual will aid those responsible for evaluation activities to demonstrate accountability to diverse stakeholders. In this case, accountability includes assessing and documenting the effectiveness of programs, measuring program outcomes, documenting implementation and cost effectiveness, and increasing the impact of programs.