Respiratory syncytial virus (RSV) infections in the institutionalized elderly have been described; however, there is little information on the impact of RSV infection on community-dwelling elderly. The purpose of this study was to determine the relative numbers of hospitalizations associated with RSV infection and compare the clinical manifestations with influenza A infection. Between November and April during 1989-1992, persons > or = 65 years old hospitalized with acute cardiopulmonary conditions or influenza-like illnesses were evaluated. Evaluation included viral culture, RSV antigen detection, and serologic analysis; 159 (10%) of 1580 had RSV infection and 221 (11%) of 2091 had influenza A. RSV and influenza A cases occurred simultaneously throughout the 3 years. Clinical manifestations were similar; however, patients with RSV infection were more likely to receive therapy for bronchospasm. Death rates were 10% and 6% for RSV infection and influenza A, respectively. RSV infection is the cause of serious disease in community-dwelling older persons.