A penicillin- and trimethoprim-resistant strain of Streptococcus pneumoniae serotype 9 was isolated from sputum, pleural effusion fluid or blood collected from 10 patients with lower respiratory tract infection on three separate wards in a hospital for the elderly over a 3-week period in February, 1993. Eight of the 10 infections were hospital-acquired. Following the cessation of new admissions to wards with infected patients, and a change of antibiotic policy for the treatment of lower respiratory tract infections, there were no new isolates. The outbreak probably resulted from failure to promptly identify, and manage appropriately infection in the index case.