Microbes show a high antimicrobial resistance due to a high rate of mutations predisposed by many factors, especially the abuse of antibiotics. Therefore, there is a great need for an alternative therapeutic agent for infectious diseases caused by microbes resistant to antibiotics. Bacteriophages are viruses parasitizing microbes, that got a big scientist’s attention due to their ability as an alternative therapy for severe bacterial infections. This study is devoted to identifying bacteriophage from river water on tested pathogenic isolates isolated from clinical cases of UTI in vitro and finding out the effect of phage on these bacterial isolates as an initial step of further in vivo phage therapeutic study on the same tested isolates. The results showed a significant bactericidal effect of the isolated bacteriophages against the pathogenic bacterial isolates.