The present invention relates to a prevention or treatment of infection by hepatitis C virus (HCV) using miR-99a-5p. More specifically, the purpose of the present invention is to provide a pharmaceutical composition for preventing or treating infection by hepatitis C virus, comprising miR-99a-5p.본 발명은 miR-99a-5p 를 이용한, C형 간염 바이러스(hepatitis C virus, HCV) 감염 질환의 예방 또는 치료에 관한 것이다.