We calculated the long-term risks of death from smoking for individuals of various ages and smoking status in terms of the excess mortality contributed by smoking, over and above the baseline mortality from the same diseases caused by factors other than smoking using standard life table procedures. Since mortality data for specific smoking categories were available only from prospective studies in the late 1950s, we scaled these to the 1982 mortality levels. We assumed, for lung cancer, that the death rates for nonsmokers have not changed and, for other smoking-related diseases, that the risks of death for smokers relative to those for nonsmokers have not changed since the 1950s. Probabilities that result from alternative assumptions were also investigated and are presented. As many as one-third of heavy smokers age 35 will die before age 85 of diseases caused by their smoking. The probabilities of death from smoking when compared with other causes may be persuasive as public education tools. Their effective use for this purpose is affected not only by the deficiencies in the public's factual knowledge of the magnitude of the risks from smoking, but also by numerous apparent misconceptions relating to the interpretation of risk information. Risk data should be presented to the public in a manner that clarifies these misconceptions and facilitates their understanding of the overwhelming risk imposed by smoking.