BACKGROUND: Diarrhea is a common disease in the neonate calf which imposes significant economic burden on cattle industry around the world. During the first week after birth, Enterotoxigenic E.coli (ETEC) strains carrying F5 fimbria are one of the most important pathogens causing calf diarrhea. F5 fimbria is involved in early stage of pathogenesis and is responsible for attachment of bacteria to enterocytes; this attachment is mediated by FanC protein of F5 fimbria. Antibodies directed against F5 fimbriae play a significant role in prevention and control of the disease. Objectives: Evaluation and expression of recombinant expression of F5 Fimbriae of Enterotoxigenic Escherichia Coli associated with calf diarrhea. Methods: In the present study,  the fanC region of F5 fimbria was cloned in a pET28a plasmid. Results: The recombinant construct was confirmed by sequencing and protein production in Escherichia coli BL21 (DE3) was evaluated by western blotting procedure. Conclusions: Based on our findings, the recombinant FanC protein or the BL21 (DE3) strain are suitable candidates to develop an effective vaccine against calf colibacillosis or use in a diagnostic kit for F5+ ETEC.