BACKGROUND: Malignant mesothelioma of the pleura is an aggressive tumor known to be associated with asbestos. Histological diagnosis of mesothelioma is challenging and is usually aided by immunohistochemical markers. METHODS: During an 18-year period (1995-2012), 66 patients with pleural mesothelioma were diagnosed at the Samsung Medical Center in Seoul. We reviewed hematoxylin and eosin and immunohistochemical slides of pleural mesothelioma and evaluated their pathological and clinical features. RESULTS: The male-to-female ratio was 1.75:1, and age of patients ranged from 28 to 80 years with an average age of 56.84 years. Twenty-two out of 66 patients underwent curative pneumonectomy. Follow-up data was available in 60 patients (90.9%), and 50 of them (83.3%) died from the disease. The average overall survival was 15.39 months. Histologically, the epithelioid type was the most common, followed by the sarcomatoid and the biphasic types. Epidemiologic information was not available in most cases, and only one patient was confirmed to have a history of asbestos exposure. CONCLUSIONS: Malignant mesothelioma of the pleura is a fatal tumor, and the therapeutic benefit of pneumonectomy remains unproven. The combination of calretinin, Wilms tumor 1, HMBE-1, and thyroid transcription factor-1 may provide high diagnostic accuracy in diagnosing mesothelioma.