Introduction: Tobacco use is the leading risk factor for lung cancer. Trends in cancer incidence among young adults are rarely studied. This article presents an analysis of trends in France over the past 30 years among people aged 20–44. Materials and methods: Observed incidence data for the period 1982–2010 for people aged 20–44 were provided by six cancer registries covering approximately 6% of the French population. Age-period-cohort models were fitted to these data, and short-term projections were provided for the year 2012. Results: Lung cancers in adults aged 20–44 accounted for 3.8% of all lung cancers observed between 1982 and 2010. Among women aged 20–44, a significant increase in lung cancer incidence was observed over the entire period. Among men, a slight decrease was observed during the study period. This decrease was more pronounced toward the end of the period. Conclusion: Although the incidence of this cancer is rare among young adults, these results show a sharp increase in incidence among young women in France. These concerning findings suggest that this population should be the target of prevention campaigns, while continuing efforts to combat smoking among men. [author’s abstract]