Proteus mirabilis is an opportunistic Gram negative bacterium belonging to the family Enterobacteriaceae. P. mirabilis is responsible for many infections in human including; urinary tract, respiratory tract, burn and wound infections and diabetic foot ulcer. The misuse and overuse of the antibiotics have led to emergence of multi-drug resistance isolates. To combat such resistance new approaches are required, one of these is the application of bacteriophages. Phages have several merits over the antibiotics including; high specificity, replication at the infection site and the biofilm degradation capability. The current study aimed to investigate the antimicrobial susceptibility pattern and the biofilm formation capabilty of P. mirabilis isolated from different sources and study the effect of the bacteriophages on the control of pre-established biofilms formed by MDR P. mirabilis. A total of 47 Proteus mirabilis isolates were obtained from 400 clinical specimens collected from patients admitted to Zagazig University Hospital and Al-Ahrar hospital in Zagazig, Sharkia Governorate, Egypt during the period from April 2016 to December 2016. The clinical specimens included urine samples, diabetic foot, burn, wound swabs and endotracheal aspirates from mechanically ventillated patients. The identification of P. mirabilis isolates was mainly based on phenyl alanine deaminase, urease, sugar fermentation test and H2S production on TSI agar slant in addition to swarming on nutrient agar. The overall frequency of P. mirabilis isolation from clinical specimens was 11.75%. The susceptibility of the P. mirabilis isolates against 17 different antibiotic disks was tested. The isolates showed complete resistance to tetracycline, while exhibited the highest resistance rates to ampicillin (91.5%), ampicillin-sulbactam (83%) and sulphamethoxazole-trimethoprim (80.9%). Lower resistance rates were found against meropenem (8.5%), imipenem (10.6%) and aztreonam (27.7%). Out of 47 P. mirabilis isolates, 41 (87.2%) were considered as multi-drug resistant. The anti-biogram typing for the isolates revealed that the isolates were epidemiologically unrelated. The ability of the isolates to form biofilm was investigated using spectrophotometric method. Except for eight isolates that showed moderate biofilm forming capacity, all tested isolates were found to be strong biofilm formers. Five different bacteriophages attacking P. mirabilis isolates were isolated from raw sewage water samples that were collected from different areas at El-Sharkia Governorate, Egypt using the double layer agar technique. On culture plates, phages exhibited different plaque morphology; PMP1, 2 and 5 produced large, circular, clear plaques and surrounded with halo. Plaques of PMP3 were small, circular, clear and surrounded with halo, while PMP4 produced small, circular, clear plaques with no halo. Phages were characterized based on transmission electron microscopy in addition to type and size of genome nucleic acid. All phages were DNA phages. PMP1 could belong to the family Podoviridae, PMP2 could belong to Plasmaviridae family, while PMP3, 4 and 5 could belong to any of the families Microviridae, Corticoviridae or Tectiviridae. The phage lytic spectra and host specificity test revealed that all phages were highly specific against P. mirabilis isolates with no effect on the other bacterial species. Each of PMP1, 3 and 4 lysed only 4 P. mirabilis isolates, each. PMP5 lysed 8 isolates and PMP2 had the widest spectrum of lytic activity, lysed 9 isolates. The effect of the PMP1, 2, 3, 4 and 5 on the eradication of 24 h old biofilm was investigated. It was found that PMP1, 2 and 3 bacteriophages had a high eradication potential on pre-formed biofilm, while PMP 4 and 5 had low to intermediate eradication activities. PMP2 was the most potent bacteriophage when tested on isolate No. 17, with 99.9% reduction in the bacterial viable counts.