The adolescent and young adult (AYA) oncology population has seen inferior progress in cancer survival compared with younger children and older adults over the past 25 years. Previously, AYAs had the best survival rates due to the prevalence of highly curable diseases including Hodgkin lymphoma and germ cell tumors, yet today AYAs have inferior survival rates to children and some adult cohorts. Survival rates are particularly poor for AYA-specific diseases such as sarcomas. Research involving children and adults diagnosed with common malignancies such as acute lymphoblastic leukemia has resulted in improved survival rates. However, AYAs have not directly benefited from such research due to low rates of access to and accrual on clinical trials. AYAs are less likely to have insurance or access to healthcare, are more likely to see providers who are not part of research institutions, and are less likely to be referred to or to join clinical trials, all of which may contribute to worse outcomes. Few clinical trials target AYA-specific diseases, leading to little information regarding how these diseases behave and what role the host plays. Tumor samples for this population are underrepresented in national tumor banks. Coupled with the need for more clinical trials that focus on AYA-specific cancers, better collaboration between adult and pediatric cooperative groups as well as increased education among community oncologists and primary care providers will be needed to enhance participation in clinical trials with the goal to increase survival and improve quality of that survival. Cancer 2007. © 2007 American Cancer Society.