Malignancies are rare young French adults but represent the third significant cause of death in the cohort of 15-24 years of age. The aim of this study was to investigate incidence and survival rates of French adolescents and young adults with cancer. All cases of cancer occuring over a 20-year period (1978-1997) in the cohort of patients aged 15 to 24, were obtained from nine population-based registries (10 % of the French population). Basal cell carcinomas of the skin were excluded. 1161 and 1884 cases were recorded in adolescents and young adults, respectively. Overall incidence rates (IR) were 161.4/10(6) in adolescents aged 15-19 years (M/F ratio = 1.3), and 252.6/10(6) in young adults aged 20-24 years (M/F ratio : 1.2). During the 1978-97 period, the IRs appeared stable over the years, +0.4 % [CI95 % = -2.3 ; +3.1] (p = 0.79) for adolescents and +1.7 % [CI95 % = -4.0 ; +7.3] (p = 0.57) for young adults. Five-year overall survival rates were 69.1 % [CI95 % = 66.4-71.8] for adolescents and 74.5 % [CI95 % = 72.3-76.7] for young adults. The 5-year survival rate for patients 15-24 years improved from 62.0 % (CI95 % = 57.5-66.5) in 1978-82 to 80.2 % (IC95 % = 77.7-82.8) in 1993-97. Noteworthy, results in adolescents and young adults are poor compared to the ones from their younger counterparts, especially in patients with acute lymphoblastic leukemia, non-Hodgkin lymphoma, Ewing's sarcoma, osteosarcoma, rhabdomyosarcoma, and astrocytoma. Further studies are warranted to elucidate whether these differences are due to intrinsic biological properties of the tumor or to differences in clinical practices in the two populations.