Hospital discharge data from Michigan for the years 1990 and 1991 were used to examine potential associations between pneumoconiosis and pulmonary hypertension, lung cancer, obstructive lung disease, and connective tissue disease among both men and women. Lung cancer, pulmonary hypertension, and obstructive lung disease were associated with coal workers' pneumoconiosis. Pulmonary hypertension and obstructive lung disease were associated with asbestosis and silicosis. Rheumatoid arthritis was associated with silicosis. The potential is suggested that misdiagnosis is the cause of the association between lung cancer and coal workers' pneumoconiosis.