Campylobacter jejuni is a Gram-negative bacterial species which is one of the most common causes of bacterial infection of the human intestine. The most common source of infection is through consuming contaminated food, but can also happen through a direct contact with an infected animal or person. Symptoms are usually not critical, but death can occur, especially in infants and elderly people. Because of the frequent, sometimes even excessive, use of antibiotics in healthcare and livestock breeding, there is a growing number of antibiotic resistant bacteria. Bacteriophages could be a good alternative for treating or preventing of such infections. Their impact on pathogenic bacteria is relatively poorly investigated and researched. We analyzed the influence of PC5 bacteriophage on the ability of C. jejuni to adhere and invade on/in CaCo-2 at different MOI. We found that adhesion and invasion is somewhat dependent on the value of MOI and that there were relatively small differences between the control and tested samples, but the differences were not statistically significant; we presumed that this happened because we introduced three separate microorganisms into the system and because the experiment consisted of a large number of steps, variables and sampling, all of which increased the possibility of analytical errors and human error. Further research is needed and it would be reasonable to try and optimize the protocol of the experiment and to possibly conduct more replicates.