A survey of 109 pulmonary physicians representing both private practice and academic medicine was conducted to learn their practice of management and treatment of interstitial lung disease. Of the 109, 25 (23 percent) responded. Twenty-two of 23 routinely obtain tissue diagnosis. The routine method was transbronchial biopsy by 15 physicians vs open lung biopsy by seven. Few (n = 5) use BAL cell analysis. The majority of clinicians used two to four criteria to initiate therapy. Physiology laboratory data were the predominant criteria used by the majority of physicians and also were most commonly used to monitor a patient's course over time. Prednisone was the drug of choice for therapy. Immunosuppressive therapy was not used until failure of steroid therapy was observed. There was little consistency in the diagnostic procedures applied, criteria for the decision to treat, the drugs used to treat, or methods for monitoring.