To determine the impact of methicillin resistance on clinical course and outcome, we evaluated nosocomial bloodstream infections (BSIs) due to Staphylococcus aureus that were diagnosed in 82 adult patients at the Medical College of Virginia Hospitals from December 1995 through May 1997. Patients with BSI due to methicillin-resistant S. aureus were compared with patients with BSI due to methicillin-susceptible S. aureus; the groups did not differ with regard to inflammatory response or outcome. Mortality was predicted by systemic inflammatory response and Acute Physiology and Chronic Health Evaluation II score but did not correlate with bacterial resistance to methicillin.