Objective: Thestudyaims to investigate the risk of post-transfusion transmission of hepatitis c virus (HCV) in the circumstances of occult HCV when anti-HCV is undetectable by ELISA and HCV-RNA is detected by RT-PCR in the plasma and or in peripheral blood mononuclear cells (PBMCs) of donor blood and the recipients are immunocompromised. Patients & methods: Thestudycovered18 chronic renal failure patients (CRF) [12 males (66.7%) their age ranged from 28 to 65 years and 6 females (33.3 %) their age ranged from 15 to 55 years] undergoing hemodialysis in Nile Hospital as part of their therapy have to receive blood transfusions (275 blood units) for the first time. Commercial ELISA kits for anti-HCV and nested-RT-PCR (N-RT-PCR) kits were used. Results: Anti-HCV was positive in one serum from the eighteen (5.5%) poly transfused CRF patients at the end of the study while the seventeen sera were negative. This serum was also positive for HCV RNA by N-RT-PCR. Out of the 20 transfused blood units, one blood unit (three components) were tested by blood banking anti-HCV negative by ELISA, were positive for HCV RNA by N-RT-PCR. The collective markers of this blood unit represent an occult HCV. The risk of acquiring post-transfusion HCV infection from an occult HCV blood unit is 5%. Real time PCR showed variation in the viral load of the serum of the infected CRF patient, the plasma of blood unit, the PBMCs of this blood unit whether activated by PHA-M or not.