BACKGROUND Our goal was to define the prevalence of radiation-induced valvular heart (RIVD) disease among patients undergoing cardiac valve surgery in a community-based, regional academic medical center. Mediastinal radiation is a treatment modality for various hematologic and solid malignancies; however, long-term cardiac complications, including radiation-induced valvular heart disease, can occur years after the radiation treatments. HYPOTHESIS Mediastinal radiation exposure is an independent risk factor for valvular heart disease often necessitating valve replacement in patients without other risk factors for valve disease. METHODS Between January 1, 1998 and September 1, 2007, we retrospectively analyzed our institution's cardiac surgical database over a 10 year period and identified 189 consecutive patients ≤ 50 years of age who underwent valve surgery. Using case-control matching, we assessed the prevalence of mediastinal radiation among these young patients with valve disease necessitating surgery and to their matched controls from all patients admitted to the hospital. RESULTS Nine individuals (4.8%) were identified as having received previous mediastinal radiation, significantly increased from controls (p<0.0001), and 8 of whom had surgical or pathologic findings consistent with radiation damage. Compared with a matched case-control population, individuals who had severe valve disease and underwent valve replacement had a markedly increased prevalence of prior mediastinal radiation therapy. CONCLUSIONS In conclusion, cardiologists must remain aware of the potential long term valvular complications in patients treated with mediastinal radiation. Increased surveillance for RIVD may be considered in the decades following radiation therapy.