Bronchogenic cysts are rare congenital anomalies located in the mediastinum and lung parenchyma. We present the clinical findings and describe the mediastinoscopic treatment of a bronchogenic cyst at the subcarinal space in a 50-year-old man. CT revealed a lesion at the subcarinal space with soft tissue density. Initially, mediastinoscopy was performed for diagnostic purposes. Histopathological evaluation of biopsy material taken from the cyst wall confirmed that the lesion was a bronchogenic cyst. The cyst contents were drained and a sclerosant agent was applied to the cyst lumen via the drainage tube. Mediastinoscopy not only provides diagnostic information but can also be used safely in the treatment of anterior bronchogenic cysts in patients not amenable to a second operation.