AIM: Assessment of neutralizing activity of the human monoclonal antibodies against HCV and also study its safety in experimental small animals (Swiss mice). MATERIALS AND METHODS: Assessment of neutralizing activity of the human monoclonal antibodies against HCV envelope regions (E1, E2) by two methods (by HCV cc infectious system and by using positive HCV positive serum as source of HCV particles (neutralizing assay 2). Dot ELISA were used to study the activity of the generated antibodies. We tested the safety and toxicity of the generated human antibodies by assessment the changes in biochemistry of liver function tests and changes in kidney function test, Complete blood counts (CBC) and study the pathological changes with different concentration of purified human antibodies. RESULTS: Human Abs # 5 & 11 showed neutralizing activity by (neutralizing assay 2) but were not neutralizing by HCV cc assay. Human Abs # 12 & 15 showed neutralizing activity by two methods i.e our generated human antibodies Abs# 5 &11 & 12 & 15 were neutralizing for HCV genotype 4a and Abs # 12 & 15 were neutralizing for HCV genotypes 4a and 2a. Liver and kidney functions and CBC results indicated that doses of 10 μg, 100 μg were safe. The histopathological results indicated that the dose of 10 μg of purified human monoclonal antibodies per mouse body weight was safe. CONCLUSION: The generated human monoclonal antibodies can be used to develop a potent immunotherapy that can be administrated for the post-transplantation patients to prevent the recurrence of HCV infection. Also, the monoclonal antibodies can be used to develop a vaccine against HCV.