Bacteroides fragilisis a commensal gut bacterium that is associated with a number of blood and tissue infections. It has not yet been recognized as one of the drug-resistant human pathogens, but cases of the refractory infections, caused by strains that are not susceptible to the common antibiotic regimes established forB. fragilis,have been more frequently reported. Bacteriophages (phages) were found to be a successful antibacterial alternative to antibiotic therapy in many cases of multidrug-resistant (MDR) bacterial infections. We have characterized the bacteriophage GEC_vB_Bfr_UZM3 (UZM3), which was used for the treatment of a patient with a chronic osteomyelitis caused by aB. fragilismixed infection. Studied biological and morphological properties of UZM3 showed that it seems to represent a strictly lytic phage belonging to a siphovirus morphotype. It is characterized by high stability at body temperature and in pH environments for about 6 h. Whole genome sequencing analysis of the phage UZM3 showed that it does not harbor any known virulence genes and can be considered as a potential therapeutic phage to be used againstB. fragilisinfections.