STUDY DESIGN: To determine the yield and diagnostic significance of performing viral cultures on specimens obtained by bronchoalveolar lavage (BAL) in immunocompromised patients. DESIGN: Review of all BAL specimens submitted for viral culture over a six-year period. SETTING: Referral laboratory within a university hospital. The majority of specimens came from the university hospital, and for those cases, review of the patient\'s underlying disease, clinical presentation, and outcome was performed. PATIENTS: Over 95 percent of the patients had recognized underlying immunosuppression. INTERVENTION: None. MEASUREMENTS AND RESULTS: Cultures were done on 1,199 BAL specimens for viruses, and in 90 (8 percent), non-cytomegalovirus (CMV) viruses were recovered. These included herpes virus (53), influenza (11), parainfluenza (7), rhinovirus (12), adenovirus (5), enterovirus (1), and respiratory syncytial virus (1). Complete medical records were available for 1,020 (85 percent) of the BAL specimens, and the 77 patients with non-CMV viral pneumonia were studied in more detail. In 31 (40 percent) patients, virus was the only potential pathogen recovered. CONCLUSION: The recovery of respiratory viruses followed epidemic trends in the community and was often associated with self-limited illnesses without an increased mortality. The isolation of herpesvirus in patients without AIDS was associated with increased mortality in comparison with patients with AIDS (p < 0.01). This study demonstrates that viruses other than CMV may be recovered from BAL of patients with lower respiratory disease and may be the only pathogen recovered.