Cancers of the respiratory system are among the most common types of malignant neoplasms in the industrialized world. Thus, this group constitute about 20% of all male and about 8% of all female cancers diagnosed in Denmark during the recent years. Altogether respiratory cancers contribute with around 3,700 (14%) new cases of the about 26,000 cancers diagnosed a year, including skin cancers. Since lung cancer, which in general have a very bad prognosis with a relative 5-year survival of 6%, is the far major cancer subtype in the respiratory system (about 90% of all respiratory cancers), the survival of all respiratory cancers combined is poor. However, the survival of the relative rarely sinonasal and laryngeal cancers are fairly good with 5-year relative survival rates in men of 47% and 61% and in women of 51% and 62%, respectively, during the 1980s. In general, only very small improvements in survival during the period of registration have been observed, the largest being in sinonasal neoplasms, where the 5-year relative survival for the men have increased from 18% around 1945 to 47% around 1985, and for the women from 30% around 1945 to 51% around 1985. Since the aetiology of the major part of respiratory cancers is fairly known, i.e. especially tobacco smoking and to some extent several factors in the working environment, it seem most likely that the major progress will come from primary prevention.