We reviewed the records of the microbiology laboratory of the Veterans Administration Medical Center, Bronx, New York in order to determine the prevalence, epidemiology and complete antibiotic susceptibility profile of amikacin-resistant aerobic and facultative gram-negative bacilli isolated from clinical specimens submitted for culture between January 1, 1980 and May 1, 1981. Of more than 5000 gram-negative rods isolated during this 16-month period, 2.8% were determined to be resistant to amikacin by the disc diffusion method. Eighty-eight of the amikacin-resistant organisms were unique isolates derived from cultures on 74 patients located throughout the hospital. Urine (51%) and sputum (27%) were the predominant sources of specimens yielding resistant strains. These organisms represented seven different genera of Enterobacteriaceae (58%) or Pseudomonas aeruginosa (31%) and other glucose non-fermenting species (11%). Resistance to amikacin was usually associated with resistance to gentamicin, tobramycin and most of the other antimicrobials tested. Twenty percent of isolates were susceptible to only a single antimicrobial, and another 5% were resistant to every agent routinely tested. Although geographic clustering of a small number of amikacin-resistant organisms occurred twice (a strain of Proteus mirabilis on the spinal cord injury service and a strain of P. aeruginosa on one medical ward), the vast majority of isolations were consistent with a pattern of endemic resistance.