Radiation-induced cardiovascular disease is well described as a late effect in cancer patients treated with radiation therapy. Advancements in surgery, radiotherapy, and chemotherapy have led to an increasing number of cancer survivors with resultant long-term side effects related to their cancer treatments. In this review, we describe the short- and long-term cardiovascular consequences of mediastinal radiotherapy and discuss the optimal cardiovascular assessments and diagnostic tools in asymptomatic and symptomatic patients.