Medicare beneficiaries are individuals who are eligible to receive benefits from the federal health insurance program known as Medicare. This program provides health coverage to individuals who are 65 years of age or older, as well as to certain younger individuals with disabilities, end-stage renal disease, or Lou Gehrig's disease. Medicare beneficiaries can receive coverage for a variety of medical services, including hospital stays, physician visits, preventive care, prescription drugs, and more. The program is divided into different parts, including Medicare Part A (hospital insurance), Part B (medical insurance), Part C (Medicare Advantage plans), and Part D (prescription drug coverage). Research on Medicare beneficiaries often focuses on understanding their healthcare needs, utilization patterns, health outcomes, and access to care. This research can help policymakers, healthcare providers, and insurance companies better tailor their services to meet the needs of this population and improve health outcomes for older adults and individuals with disabilities.