BACKGROUND In the U.S., adolescents and young adults diagnosed with cancer have had less survival improvement than older or younger patients, a deficit that may be a result of delays in diagnosis in an age group with the lowest rates of health insurance. METHODS The relationship between health insurance status and the time from the onset of first cancer-specific symptom or sign to definitive diagnosis (lagtime) was retrospectively compared with other sociodemographic factors in newly diagnosed cancer patients aged 15-29 years who were evaluated between June 2001 and June 2003. Data on 270 patients with the six most common cancer types in this cohort (leukemia, Hodgkin's and non-Hodgkin's lymphoma, sarcoma, brain tumors, thyroid cancer) were retrospectively collected in 2004. RESULTS Lagtimes were evaluable in 235 (88%) patients. In multivariate analysis, the type of cancer and health insurance were significantly associated with lagtime, whereas race/ethnicity, age, gender, marital status, and surrogate measures of socioeconomic status were not. The mean lagtime in patients with public or no health insurance was 13.1 weeks longer than in patients with private health insurance, and longer in four of six evaluable histology-specific types of cancer. In cancers evaluable for stage at diagnosis, advanced stage was associated with longer lagtimes. CONCLUSION In the U.S., older adolescents and young adults with cancer are likely to have a delay in diagnosis because of inadequate health insurance and consequently present with a more advanced stage of disease.