In 1986, the Surgeon General concluded that smokeless tobacco is an addictive drug sharing many qualities with other drugs of abuse such as morphine and cocaine. Smokeless tobacco can be used to deliver psycho-active and dependence-producing levels of nicotine. Tolerance develops with repeated use, causing the user to increase nicotine dosing through increased use and/or switching to products with higher nicotine yields. Clinical signs of nicotine withdrawal develop upon cessation of use. Recent data show that smokeless tobacco products vary widely in their nicotine dosing capabilities. Low-dose products tend to be those commonly marketed toward, and used by, young people without previous smokeless tobacco experience. Many of these people develop dependence and switch to high-dose products. The present article discusses each of these qualities of smokeless tobacco in greater detail. The article also discusses qualities of smokeless tobacco that make it an effective nicotine delivery device that leads to addiction.