Background: Cancer has substantial health, quality-of-life, and economic impacts. Screening may decrease cancer mortality and treatment costs, but the cost of screening in the United States is unknown. Objective: To estimate the annual cost of initial cancer screening (that is, screening without follow-up costs) in the United States in 2021. Design: Model using national health care survey and cost resources data. Setting: U.S. health care systems and institutions. Participants: People eligible for breast, cervical, colorectal, lung, and prostate cancer screening with available data. Measurements: The number of people screened and associated health care system costs by insurance status in 2021 dollars. Results: Total health care system costs for initial cancer screenings in the United States in 2021 were estimated at $43 billion. Approximately 88.3% of costs were attributable to private insurance; 8.5% to Medicare; and 3.2% to Medicaid, other government programs, and uninsured persons.