Background and Aims: Fresh Frozen Plasma (FFP) is one of blood components. The risk of transmission of viruses from blood components regardless selection of blood donors and screening donated blood still remains. There are several methods for viral inactivation. In this study methylene blue (MB) photo inactivation process was used for inactivating viruses. Materials and Methods: In this study Methylene Blue(MB) was used in final concentration of 1µM. Infected Fresh Frozen Plasma (FFP) illuminated by 143Pieces (PCs) of 1 w red Light Emitting Diodes (LEDs) from two side for 10,15 and 30 minutes and shacked 30 cycle in minutes. The central wavelength of these LED is 627 nm with 20 nm Full Width at Half Maximum (FWHM).Herpes simplex virus-1(HSV-1) and vesicular stomatitis virus (VSV) were used as model viruses to evaluated illumination effects on viral inactivation. Level of fresh frozen plasma (FFP) coagulation factors such as fibrinogen, FV, FVIII, protein C, antitrombin measured pre and post illumination. Results: Initial HSV-1 and VSV titer were calculated to be 107 and 106.5 TCID50/ml, respectively .The level of viral inactivation was expressed as log-reduction. Titer reduction of HSV for 10, 15 and 30 minutes irradiation with shaking was>6, &ge7 and &ge 7 logs, respectively. The ratio of coagulation factors activity remaining unchanged after pathogen inactivation with MB calculated. Illumination had major effects on the mean levels of fibrinogen and FVIII. Significant differences between level of factors before and after illumination were evaluated with a t test for paired samples. No significant differences were seen in the FFP coagulation factors before and after illumination (P˃0.05). Conclusion: As results show the optimum time for viral inactivation were adjusted to be 15 minutes. Due to the reduction of virus titer at various times, agitation with illumination is effective.