Three cases of spontaneous peritonitis caused by Enterococcus faecium are presented. The underlying condition was alcoholic cirrhosis in each case. This enterococcal species has never before been reported as a cause of spontaneous bacterial peritonitis. Two patients responded to therapy. The development of enterococcal peritonitis and the cases documented in the literature are briefly reviewed. Taxonomic problems with pathogenic, clinical, and therapeutic implications are discussed.