This paper examines changes with time of mortality from lung cancer in Italy during the years 1950-1979 in relation to changes in smoking habits since 1900. In both sexes and for all ages mortality rose throughout this period, although for women the rates and the relative increases per year have been consistently much lower than for men. Between 1950-1952 and 1977-1979 the age-adjusted death rate per 100,000 men rose almost five times (from 10.01 to 49.55) whereas that for women only doubled (from 2.65 to 5.74), so that the male/female ratio increased from 3.78 to 8.65. In men successive cohorts show an increase of age-specific death rate, but there are indications that for men born after 1925 the mortality rate is beginning to level off. In women over 50 years of age mortality continues to rise, but below this age it tends to level off and decline. Analysis of the consumption of different types of tobacco products since 1900 suggests that the trends of mortality with time in different birth cohorts are explicable in terms of changes of use of cigarettes.