OBJECTIVE To report a case of empyema caused by Streptococcus intermedius as a complication of community-acquired pneumonia (CAP). METHODS An 85-year-old woman with a history of chronic obstructive pulmonary disease, asthma, heart failure, and hypothyroidism developed empyema as a result of 2 episodes of CAP and an acute exacerbation of chronic bronchitis within the past 2 months. Therapy with intravenous levofloxacin 750 mg every 48 hours was initiated. Culture results of the empyema fluid yielded pure growth of a rarely encountered microorganism, S. intermedius. Intravenous piperacillin/tazobactam 3.375 g every 6 hours was added to the antimicrobial therapy at that time. However, cultures continued to show S. intermedius. Surgical decortication was unsuccessful, and the patient died after a 30 day hospital stay. CONCLUSIONS Early, appropriate antimicrobial therapy is the mainstay of CAP treatment. Although rare, empyema or thoracic abscess can occur despite this therapy, due to mucosal changes caused by CAP. Historically, antimicrobial therapy used to treat organisms that typically cause CAP also has activity against S. intermedius. However, growth of this microorganism and failure to respond to therapy should alert clinicians to the possibility of empyema or abscess formation. CONCLUSIONS Despite historical in vitro susceptibility data of S. intermedius, antimicrobial therapy may be ineffective, and more extreme measures may be needed to achieve a successful outcome. Early, appropriate antimicrobial therapy needs to remain the mainstay of the treatment of CAP in an attempt to prevent fatal complications such as this from occurring.