The antibiotic therapy has many problems, such as antibiotics resistance, hypersensitivity, direct toxicity, antibioticinduced immunosuppresion and super-infections. This is highlighting the need for a new strategy for non-antibiotic therapy through the use of novel immunomodulators as naturally released ones (Lactoferrin). The present study investigates the potential of bovine lactoferrin (bLf), isolated from bovine milk whey, to prevent Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), Streptococcus agalactiae (S. agalactiae) and Pseudomonas aeruginosa (P. aerogenosa) growth and then evaluates its immunomodulator effect. First, bLf isolation was attempted from bovine milk whey using a cation exchange chromatography by SP-Sepharose. Second, the antimicrobial activity assays were trailed to study the antimicrobial activity of bLf. Finally, the immune effect of bLf was studied by lymphocyte transformation test. It was found that bLf was separated around molecular weight of 80 kDa and showed significant inhibitory effect against E. coli followed by P. aeruginosa, S. agalactiae and S. aureus. bLf increased lymphocyte transformations mean values in a dose dependant manner. The highest transformations mean value was determined at 50 µg/mL. In conclusion, these results suggest that bLf is a potent natural antimicrobials and immunomodulator agent.