OBJECTIVE: To describe the epidemiology of and clinical findings associated with a rhinovirus outbreak that occurred among institutionalized elderly persons. DESIGN: Retrospective review of medical records and nursing surveillance reports. SETTING: A 685-bed, long-term care facility for veterans and their spouses. PATIENTS: 33 persons from whom rhinovirus was cultured. MEASUREMENTS: Throat and nasopharyngeal virus culture; review of medical records to determine underlying diseases, signs and symptoms of respiratory illness, illness duration, and interventions during illness; and review of nursing surveillance reports to determine room locations of ill persons. RESULTS: Between 14 August and 2 September 1993, the number of respiratory illnesses increased. Throat and nasopharyngeal virus cultures were taken from 67 ill residents; 33 cultures yielded rhinovirus, and no other respiratory virus was isolated. Geographic clustering of persons infected with rhinovirus was observed. Of those persons with rhinovirus infections, 100% had upper respiratory symptoms, 34% had gastrointestinal symptoms, 71% had systemic symptoms, 66% had lower respiratory symptoms (including productive cough), and 52% had new abnormalities on lung auscultation. The 17 persons with rhinovirus infection who had chronic obstructive pulmonary disease had more severe illnesses: Five (29%) required glucocorticoid or bronchodilator therapy for illness-associated bronchospasm; 2 required transfer out of the facility; 1 developed a radiographically documented infiltrate; and 1 died of respiratory failure. CONCLUSIONS: Rhinovirus may cause epidemic, clinically important respiratory illness in nursing homes residents. A large proportion of residents may become ill, and infection may be severe in persons with underlying lung disease.