The objective of this study was to determine the incidence of fecal coliforms in Sierra Nevada wilderness area rivers, streams, and lakes. Collection sites were selected at over a 200-mile area of the Sierra Nevada mountains in California beginning south at the Golden Trout and ending north in the Desolation Wilderness. Samplings included wilderness areas within Yosemite, Sequoia and Kings Canyon National Parks. A total of 104 samples were collected from 90 different sites. Sites were sampled during the summer of 2002. Water samples were collected using a Coli-Count Samplers (Millipore). Eighteen mL of water was collected. A culture media paddle was placed in contact to absorb 1 mL of solution. The remaining water was discarded and the filter/paddle was then incubated at 35degreeC and results read at 24 hours. At selected sites, an additional 10ml of water was transported directly to the lab in sterile test tubes to determine bacteria viability. Bacteria were sub-cultured and identified utilizing standard microbiology laboratory techniques. Coliform bacteria were found in 24 samples at a concentration ranging from 1 to 200 CFU/ml. Coliforms were found downstream from areas used for cattle grazing or heavily used by wilderness backpackers in 20 of 24 coliform positive samples. Subculture and identification of selected coliform colonies yielded E. coli. In addition, other bacteria that were identified included Yersinia enterocolitica, Enterobacter aerogenes, Serratia spp., Aeromonas hydrophila/caviae, and Pseudomonas spp. Coliforms can be found in pristine wilderness water, downstream from cattle grazing and human camping areas.