Abstract Background Head and neck cancer (HNCA) survivors have a high risk of developing cardiovascular disease (CVD) or stroke because of sharing risk factors of disease. Therefore, we investigated the risk of CVD or stroke occurrence among HNCA survivors in Korea based on the Health Insurance Review and Assessment (HIRA) Service claims database. Methods We retrieved claims data of patients who were diagnosed with HNCA in 2014‐2015 using ICD‐10 code and followed up data until 2018. Patients with newly diagnosed with CVD or stroke after HNCA diagnosis during the follow‐up period were detected. We analyzed the characteristics of patients with HNCA who were subsequently diagnosed with CVD or stroke. In addition, the risk factors of CVD or stroke occurrence were investigated using Cox proportional hazard regression analysis. Results Among the 8288 patients with HNCA, 477 and 404 patients were diagnosed with new‐onset CVD and stroke, respectively. Patients with hypertension, diabetes mellitus (DM), and hyperlipidemia had a 3.25‐fold higher risk of CVD comparing to patients without any underlying disease (95% confidence index [CI], 2.38‐4.45) Patients with three underlying diseases had a 2.92‐fold higher risk of stroke compared to patients without any underlying disease (95% CI 2.03‐4.21). Conclusions HNCA survivors with hypertension, DM, and hyperlipidemia should be cautious of the risks of CVD and stroke.