A search of the literature revealed few references to the normal enteric flora of non-human vertebrates in general and the llama, Lama glama, in particular. The bacteriologic flora of the llama as a research project was suggested by my major professor, Dr. Fuad M. Nahhas, after it was brought to his attention by one of his assistants in the microbiology department of Dameron Hospital (Stockton, CA) that her pet llama was suffering from diarrhea. Fecal material from the llama was cultured and Yersinia enterocolitica was recovered. At the same time normal bacterial flora resembling those isolated from human material were also found. In seeking a research project I thought a bacteriologic examination of fecal material from llamas would be of some interest. A search of the literature revealed a great deal of information about parasitic infections of the llama, particularly by South American parasitologists and veterinarians,. but little information on the bacteriologic flora. Most of the published reports discuss enteric pathogens and enteric diseases (Fowler, 1989). Equally scarce are reports on the antibiotic pattern of such isolates; most reports on antimicrobial activity are limited to determining which drugs are effective in the treatment of a particular infection (Timoney et al, 1988). In contrast with this, Gram negative isolates from human intestinal material are well known and their antibiograms well documented in the literature as well as in unpublished hospital records. The use of antibiotics, discriminately or indiscriminately, in the treatment of human infections and the addition of antibiotics, especially tetracycline, to animal feeds to promote growth have led to the emergence··of resistant strains among these bacteria. To what extent such resistance exists in, has crossed over to, or has been exchanged among the intestinal isolates of humans and other vertebrates is not known. The objective of this study is, therefore, twofold: 1) to conduct a survey of the Gram negative aerobic intestinal bacterial flora of llamas to determine what species are present and their relative abundance; 2) to compare their biochemical (biotypes) and antibiotic patterns (antibiogram) with isolates from other animals and humans where information is available.