Objective: Houseflies are vectors responsible for the mechanical transmission of pathogens acquired from feeding in feces and decayed organic debris. Human consumption of such food without warming could lead to gastroenteritis, a major public health problem. The aim of this research was to evaluate the range of microbial pathogens associated with the external surfaces of fly vectors and to determine the antibiotic susceptibility pattern of the bacterial pathogens. Materials and Methods: A total of 150 houseflies were collected with a sterile net from different parts of Umuahia, Abia State. Their external surfaces were screened for bacteria, fungi, and protozoan parasites in the Microbiology Laboratory of Michael Okpara University of Agriculture, Umudike by standard microbiological procedures. Antibiotic sensitivity pattern of bacterial isolates was carried out by disc diffusion method. Results: The most frequently observed microorganisms were Escherichia coli (22.9%), Klebsiella spp. (16.6%), Staphylococcus aureus (14.6%), Aspergillus spp. (28.3%), Mucor spp. (21.7%), Entamoeba histolytica (32.7%), and Endolimax nana (30.9%). Houseflies from broken sewage had the highest total viable counts and frequency of bacteria, fungi, and parasites. Bacterial isolates from houseflies gotten from health-care facilities showed higher levels of multiple drug resistance to ampicillin and cotrimoxazole. Conclusion: In this study, pathogenic microorganisms were recovered from the external surface of houseflies, the vectoral agents of mechanical transfer of microbial contaminants to exposed food. Most of the microorganisms observed in this study are known pathogens that can cause gastroenteritis which is a public health concern.