| This study was conducted for the preparation and extraction of specific Pseudomonas aeruginosa transfer factor (TFt) from rats immunized with this pathogen and to evaluate its efficacy to protect the recipient mice against challenge with virulent P. aeruginosa. Two groups of rats (each one of six rats) were used, the first group was immunized subcutaneously (S.C) twice in two -week intervals with the whole sonicated antigen, the second group (control) was inoculated S.C with phosphate buffer saline (PBS). The immunized and control rats were monitored daily for the appearances of any clinical signs along one week post each immunization, and checked for the delayed hypersensitivity (DTH). Only the immunized rats revealed positive skin test reaction. The TFt were extracted from the spleen cells of the immunized rats, tested for sterility and safety. To evaluate the efficiency of the prepared TFt, three groups of mice (each of ten) were used. The first group was injected intraperiloneally (I/P) with 0.5 mL of TFt equivalent to 5x10 8 cells/mL, the second group (positive control) was immunized S.C with 0.5 mL of sonicated P. aeruginosa, while the third group injected S.C with 0.5 mL PBS (negative control). Later on, all the mice were tested by DTH -skin test. The immunized and TFt recipient mice showed a positive skin reaction, while the control group did not reveal any skin reaction. One week later, all the mice were challenged by I.P inoculation of 0.5 mL containing 5x10 7 CFU of P. aeruginosa, the survival rates were 90%, 80% and 10% in vaccinated, TFt recipient and control mice respectively. The results of the current study demonstrated the ability of the TFt to transport the specific DTH-skin reaction to the recipient non sensitized mice in addition, to its efficacy as immunotherapy to protect them against experimental challenge with P. aeruginosa.