Bronchoscopy and bronchography have recently been becoming routine examinnations in the diagnosis of respiratory diseases.We experienced four unusual cases of bronchogenic carcinoma originated from an abnormal branch of the bronchus, which had deen diagnosed by both bronchography and bronchoscopy. Three of those originated from the right lung and the remaining one from the left lung, Of three cases from the right lung, one from an accessory cardiac bronchus and the two were from right tracheal bronchus. One case from the left lung developed from an abnormal branch of B-4.Bronchography revealed an abnormal branch in all four cases and bronchoscopic brushing cytology under general anesthesia was diagnostic of bronchogenic carcinoma in three cases. The remaining one case was confirmed to be adenocarcinoma by resection.