To evaluate the impact of open lung biopsy on diagnosis and treatment of diffuse infiltrative lung disease, we conducted a retrospective review of 28 patients who underwent this procedure at the Kyoungpook National University Hospital from 1986 to 1993. There were 19 men and 9 women; average age was 50.9 years. During open lung biopsy, The region of the lobe was radiographically and grossly identified and was examined by a biopsy. The biopsy yielded a specific diagnosis in 27 [96.4 % patients and changes in therapy in 24[85.7% patients. Complications developed in three[10.8% patients, directly related to the biopsy procedure in 2. One patient died[3.6% due to underlying disease. We conclude that open lung biopsy can be accomplished safely in the patient with diffuse infiltrative lung disease and it is an important tool in decision-making process and therapy.