OBJECTIVE To evaluate the clinical relevance and impact of an emerging bacterial pathogen, Staphylococcus lugdunensis, in a large teaching hospital. METHODS Three-year retrospective microbiological and clinical review of all S. lugdunensis isolates from a single medical center. RESULTS Seventy-seven isolates were identified; 70 had complete data. Soft tissue, bone, joint, central nervous system, urine and bloodstream infections occurred. Soft tissue infections were primarily abscesses. There were four infections of prosthetic joints and nine cases of osteomyelitis. There were 21 bacteremias, 5 of which were associated with endocarditis; 2 died. Most isolates were penicillin resistant. CONCLUSIONS S. lugdunensis has emerged as a major human pathogen, capable of causing significant infections at many sites. It should never be dismissed as a contaminant without careful review.