Serratia marcescens is recognized as an important and potentially hazardous nosocomial pathogen. The organism has been implicated here as the first reported case of S. marcescens meningitis associated with skin disinfection. A quaternary ammonium compound ( QAC --Benzalkonium Chloride), was used to sterilize the skin prior to injection in a physician's office. Epidemiological studies were initiated. Six spray bottles containing disinfectant, the opened stock bottle of QAC , and an unopened bottle of disinfectant were all cultured. S. marcescens was noted growing in the spray bottles as well as in the opened stock bottle. Antibiograms of the patient and epidemiological isolates are essentially the same. It is our contention as well as that of the Centers for Disease Control that an appropriate skin disinfectant such as Tincture of Chlorhexidine, Iodophors , or Tincture of Iodine should be used, and that physicians performing surgical techniques in the office be aware of the potential hazard of contamination. The consequences of nosocomial infection with resistant organisms warrant every precaution by health care professionals.