Abstract. Sheilahrusi, Priyanto JA, Rismiyati H, Rusmana I, Budiarti S. 2021. Short Communication: The potency of lytic bacteriophage isolated from various environments to control the growth of Citrobacter braakii causing urinary tract infection. Biodiversitas 22: 5550-5554. Citrobacter braakii is one of the pathogenic bacteria causing urinary tract infection (UTI) in humans. Bacteriophages that are specifically infecting C. braakii could be the alternatives to combat antibiotics resistance cases of this bacterium. This study aimed to isolate lytic phages from various environmental samples (tofu factory wastewater, sewage water, rice field water, fishpond water, cattle farm wastewater, and goat farm wastewater), and to analyze their effectivity to reduce UTI-causing C. braakii population in vitro. Results exhibited that phages targeting this bacterium were found in goat and cattle farm wastewater and not present in other samples. Two phages, namely FC1 and FC2, had different plaque morphology characteristics. The number of phages in cattle farm wastewater was 2.8 × 105 PFU/mL and 1.32 × 104 PFU/mL in goat farm wastewater. It was observed that the phages found in these environments also indicate the presence of their host. After 8 h incubation, FC1 and FC2 phage reduced UTI-causing C. braaakii population in vitro from 0.23×108 CFU/mL to 0.03×108 CFU/mL and 0.02×108 CFU/mL, respectively. The phages isolated from these two samples can be further developed for the treatment of UTI caused by C. braakii and goat and cattle farm wastewater treatment to prevent contaminating other areas.