Cefixime, a broad-spectrum, orally active cephalosporin, was more active in vitro than ampicillin, cefaclor, cephalothin, and trimethoprim/sulfamethoxazole against 194 nosocomial pathogens of the family Enterobacteriaceae. Activity was especially good against Klebsiella spp, Proteus spp, Serratia spp, and Providencia stuartii. Although gentamicin had equivalent or better activity against Citrobacter spp, Enterobacter spp, Escherichia coli, and Morganella morganii, all 23 of the gentamicin-resistant strains studied were susceptible to cefixime. Isolates tested were from urinary tract infections, abdominal infections, wounds, vascular infections, and respiratory infections; they were sequentially collected nosocomial pathogens from a single institution. This orally active cephalosporin should be considered for therapy of a variety of nosocomial infections involving gram-negative bacillary pathogens.