Background: Human papilloma virus (HPV) vaccination prevents the development of HPV-associated malignancies. Adolescent and young adult (AYA) survivors of childhood cancers and patients with sickle cell disease (SCD) are two vulnerable patient populations who would significantly benefit from HPV vaccination. Objective: In this mixed method study we determine the HPV vaccination rate amongst the AYA SCD and childhood cancer survivor populations. We then sought to describe patient and caregiver beliefs regarding HPV vaccination. Design/Method: We performed a retrospective chart review looking at vaccination status for patients seen in our clinics in 2019. Qualitative data was then collected via audio recorded interviews. Interviews were analyzed with a thematic content approach to understand attitudes regarding the HPV vaccination. Results: We found a notable difference between the rate of HPV vaccinations and other age-appropriate vaccinations in our childhood cancers survivors and patients with SCD. Qualitative interviews found that caregivers and AYA’s relied heavily on physician, recommendations for HPV vaccination, with a preference for subspecialist recommendation. A strong recommendation from a trusted subspecialty provider would create reassurance about vaccination and reduce misconceptions and concerns for side effects in the context of a chronic illness. Conclusion: Counseling from subspecialists could have a strong impact on understanding of the HPV vaccine in the context of chronic illness. This would likely help overcome many of the barriers to vaccination that are encountered by patients with SCD or oncology survivors.