The prevalence of multiple primary malignant neoplasms in a single patient is reported in a wide variation. The co-existence of malignant mesothelioma and pulmonary carcinoma is a rare entity. Herein, we reported a 60-year-old man who was a retired employee and heavy smoker. He had a suspicious history of asbestos exposure. He complained of chest pain and computerized tomography revealed a mass in the lower lobe of left lung. The patient underwent a left lower lobectomy and was diagnosed as pulmonary adenocarcinoma. During follow-up two years after surgery, the patient complained of dyspnea and chest computerized tomography scan revealed right pleural effusion and diffuse pleural thickening. For the differential diagnosis, the patient underwent wedge biopsy from the right lower lobe and was diagnosed as epithelial diffuse malignant mesothelioma. The development of malignant pleural mesothelioma and lung carcinoma could be associated with asbestos exposure. However, a history of asbestos exposure is not required for the diagnosis. The influence of effective anticancer therapies that improve the survival rates and increase the population ages could be related to the occurrence of a second malignancy.