The purpose of this study was to describe the impact of asthma and chronic obstructive pulmonary disease (COPD) in the elderly on health care utilization. The Health Care Financing Administration (HCFA) file for the year 1984 through 1991 involving beneficiaries < or = 65 yr were searched for the diagnoses of asthma and COPD by ICD-9 codes. The study groups were created by determining the first admission for an exacerbation of either disease during each year from 1984 through 1991. Patients were identified by their social security number. The 1984 cohort consisted of 56,692 patients with asthma exacerbation and 162,899 with COPD exacerbation. The 1991 cohort consisted of 67,758 patients with asthma exacerbation and 131,974 patients with COPD exacerbation. In addition, the 1984 cohort was tracked by social security number for evidence of rehospitalization for either asthma or COPD through 1991. Length of hospitalization increased as patients grew older. The discharge rate to an independent living facility diminished as age increased. The use of convalescent and nursing homes or home health care after discharge more than doubled from 1984 through 1991. The utilization of health care resources by elderly patients with asthma and COPD is immense, both during hospitalization and after discharge.