We studied possible explanations for the deteriorating survival for adenocarcinoma of the lung between 1975 and 1994 in relation with trends in incidence. The proportion of adenocarcinoma among men has been increasing since 1975 and for those born after 1920, while survival has decreased since 1975 and for those born since 1930. Among women, both the proportion of adenocarcinoma and survival have remained more or less constant. The rising incidence and the decreasing survival may both be related to changes in tobacco use, the increased use of low-tar filter cigarettes since the 1960s being the most likely candidate.