BACKGROUND: Young adults have historically been the least likely to have health insurance in the United States. Previous studies of survivors of childhood cancer found lower rates of insurance and less access to medical care compared with siblings; however, to the authors knowledge, no studies to date have examined continuity of insurance after a cancer diagnosis in adolescents and young adults (AYAs). METHODS: Using the AYA Health Outcomes and Patient Experience study, a cohort of 465 individuals aged 15 to 39 years from participating Surveillance, Epidemiology, and End Results registries, we evaluated changes in and sponsors of health insurance coverage after diagnosis, coverage of physician-recommended tests, and factors associated with lack of insurance after a cancer diagnosis using chi-square tests and multivariable logistic regression. RESULTS: Greater than 25% of AYA survivors of cancer (118 survivors) experienced some period without insurance up to 35 months after diagnosis. Insurance rates were high in the initial year after diagnosis (6 months-14 months; 93.3%) but decreased substantially at follow-up (15 months-35 months; 85.2%). The most common sponsor of health insurance was employer/school coverage (43.7%). Multivariable analysis indicated that older survivors (those aged 25-39 years vs 15-19 years; odds ratio, 3.35 [P < .01]) and those with less education (high school or less vs college graduate; odds ratio, 2.80 [P < .01]) were more likely to experience a period without insurance after diagnosis. Furthermore, > 20% of survivors indicated there were physician-recommended tests/treatments that were not covered by insurance, but > 80% received them regardless of coverage. CONCLUSIONS: Insurance rates appear to decrease with time since diagnosis in AYA survivors of cancer. Future studies should examine how new policies under the Patient Protection and Affordable Care Act extend access and insurance coverage beyond initial treatment.