The resources of the New Mexico Tumor Registry were adapted to identify new cases of interstitial lung disease in Bernalillo County. Other sources of information for identifying new cases included pulmonary physicians, primary care physicians, death certificates, and autopsies. After a case of interstitial lung disease had been identified from the various sources of information, data collection included an interviewer-administered symptoms questionnaire, abstracted medical record data, phlebotomy for measurement of serum precipitins, and evaluation of available chest x-rays and biopsy materials. Follow-up was used to determine the natural history of the disease.