The purpose of this study was to investigate the microorganisms found in the intestines of dogs fed commercial feed though the aerobic culture of dog excrement. 16 specimens of pet dog feces were cultured employing BAP, MaC, and EMB medium. Strains of Escherichia coli were detected in all the cultured specimens, along with a few other bacteria of significance. All 16 samples were identified as containing multiple E. coli strains using a API20E kit. Two samples showed a swarming phenomenon in the BAP medium that was identified as a Proteus mirabilis strain. In 10 samples, only E. coli species were identified, while E. coli species and P. mirabilis species were identified in 2 samples. A small number of E. coli and gram-positive bacteria were detected in 3 specimens, and a small number of E. coli and gram-positive rods were detected in one specimen. It has been shown that E. coli is predominantly distributed in the feces of dogs fed with commercial feed. The fact that E. coli is distributed in the feces of dogs is of concern as it can cause serious problems such as water pollution and food poisoning.