A 74-year-old man who had been diagnosed with malignant mesothelioma developed malignant lymphoma of B-cell origin involving the penis. He had a history of occupational exposure to asbestos as a construction worker. The association of malignant mesothelioma with lymphoma is rare, and the possibility of asbestos exposure as a common etiology is discussed. The intense stimulation of B lymphocytes and decreased T lymphocyte activity in asbestos-exposed populations may result in development of B-cell malignancies. Though the relationship between asbestos exposure and malignant mesothelioma is firmly established, the relationship between asbestos exposure and lymphoma remains to be investigated.