Background: Deafblindness is a distinct disability with major implications for communication, mobility, access to information, and participation. Population estimates vary substantially. Methods: We conducted a secondary cross-sectional analysis of nationally representative Spanish microdata from EDAD-Households 2020 and EDAD-Centres 2023, including persons aged ≥ 6 years. Functional deafblindness was defined as severe limitation in one sensory domain with at least moderate limitation in the other, accounting for residual functioning with assistive products. Weighted prevalence estimates and approximate 95% uncertainty intervals (UI) were obtained using a cluster bootstrap. Results: The integrated population represented 44.9 million persons. The primary definition identified an estimated 45,951 persons with functional deafblindness, corresponding to 102.3 per 100,000 population (95% UI, 82.5–125.1). Prevalence increased markedly with age, reaching 438.0 per 100,000 among persons aged ≥ 65 years. A broader sensitivity definition yielded 202.3 per 100,000 (95% UI, 175.8–231.2). Conclusions: Functional deafblindness affects tens of thousands of people in Spain and is concentrated at older ages and in residential settings. Population-based estimates are needed to complement administrative data and inform equitable planning of specialized, accessible health, social-care, and communication services.