Previous studies suggested that the characteristics of young female lung cancer patients may differ from those of other patients. Using the cancer registry at the Lungenklinik Heckeshorn hospital, all female patients under the age of 46 yrs with primary lung cancer 1986±1995 were identified. The clinical records were reviewed for risk factors, stage, histology, therapy, and survival. The data were compared with those of other patients.Of the 4,939 patients 96 (1.9%) were females aged <46 yrs. The percentage of young females doubled within ten years from 1 to 2% of all patients (p=0.03). The main risk factor in young females was smoking. Adenocarcinoma and carcinoids were overrepresented, whereas squamous cell and small cell carcinoma were significantly rarer in the young female group. Young females and young males were more likely to have advanced disease and underwent surgery and/or combined treatment significantly more often than older patients. The overall survival was only moderately better in younger patients.The clinical features of young female patients differed from those of young males and older females, the prognosis likewise depended on tumour stage and therapy. Eur Respir J 2000; 16: 986±990.