ABSTRAKTelah dilakukan penelitian Cross Sectional tentang prevalensi Escherichia coli pada saluran pernapasan bagian atas sapi bali menurut tingkat kedewasaan (pedet, dara, dewasa) dan perbedaan geografis (dataran rendah dan tinggi). Metode isolasi dan identifikasi menurut Carter dan Cole dengan modifikasi dan kepekaan terhadap antibiotika sulfametoksasol, ampisilin, dan oksitetrasiklin menggunakan metode difusi cakram Kirby dan Bauer. Dari 120 sampel usap hidung sapi bali, berhasil diisolasi 14/120 (11,66%) E. coli. Berdasarkan tingkat kedewasaan, pada sapi pedet ditemukan 7/120 (5,83%), dara 3/120 (2,50%), dan dewasa 4/120 (3.33%). Berdasarkan letak geografis pada dataran rendah ditemukan sebanyak 8/120 (6,66 %) dan pada dataran tinggi ditemukan sebanyak 6/120 (5,00%). Enam dari total 14 isolat E. coli (42,85%) resisten, 3/14 (21,42%) intermedier, dan 5/14 (35,71%) sensitif terhadap sulfametoksasol. Uji terhadap ampisilin 4/14 (28,57%) resisten, 1/14 (7,14%) intermedier, dan 9/14 (64,28%) sensitif. Uji terhadap oksitetrasiklin 1/14 (7,14%) resisten, dan 13/14 (92,85%) sensitif. Sebanyak tiga isolat (21,42%) peka terhadap semua antibiotika yang diujikan dan satu isolat (7,14%) resisten terhadap semua antibiotika. ABSTRACTA Cross Sectional study to determine the prevalence of Escherichia coli on bali cattle respiratory tractbased on maturity level (calves, heifers, adult) and geographical location (highland and lowland) have been conducted. The isolation and identification of bacteria based on the method of Carter and Cole with slightly modification and antibiotic sensitivity test were performed using the disc diffusion method by Kirby and Bauer. Escherichia coli was isolated from 14 out of the 120 samples (11.66%). Based on the maturity level, was found 7/120 (5.58%), 3/120 (2.50%), and 4/120 (3.33%) from calves, heifers, and adults, respectively. Meanwhile, based on the geographical location, 8/120 (6.66%) E. coli was isolated from the highland and the remains 6/120 (5.00%) from lowland. The antibiograms showed that 6/14 (42.85%), 3/14 (21.42%), and 5/14 (35.71%) of the isolates were resistant, intermediate, and sensitive to sulfamethoxazole, respectively. Whereas 4/14 (28.57%), 1/14 (7.14%), and 9/14 (64.28%) were resistant, intermediate, and sensitive to ampicillin. One isolate (7.14%) was resistant to oxytetracycline and the remains 13/14 (92.85%) were sensitive. Three isolates (21.42%) were sensitive to all tested antibiotics and one isolate (7.14%) resistant to all antibiotics.