In several countries, increased incidence of squamous cell carcinoma (SCC) of the tongue in young adults has been suspected during the last decades. Some reports indicate a lower survival rate for young patients compared to older patients. In other reports, there has not been any considerable difference in survival when comparing young adults to older patients, whereas some authors have shown better survival for young adults. This disease is rare in young adults, and early reports were based on comparable small numbers and selected patients. Our aim was first to perform a population-based study to determine if an increased incidence in SCC of the tongue could be verified in a larger population comprising the Scandinavian countries Denmark, Finland, Sweden and Norway. A second aim was to determine survival rates for young adults compared to older patients. The material was based on the annual cancer incidence and survival reports from the Scandinavian cancer registries. The study period was 1960-1994. During that period, 5,024 SCCs of the tongue were reported. Of these, 276 (5.5%) were young adults (20-39 years). The incidence increased at all ages except for women 65-79 years old. The increase was most pronounced in young adults: 0.06-0.32 for men and 0.03-0.19 for women, counted by 100,000 person-years. Relative survival was significantly better for young adults compared to older patients.