Nordihydroguaiaretic acid (NDGA) is a lignan present in the perspired resin of leaves of Larrea divaricata . This compound and its derivatives have “in vitro” inhibition against several viruses including HIV, herpes simplex I and II, and human papilloma. Junin virus is the etiologic agent of Argentine Hemorrhagic fever of great sanitary importance in Argentine. It is an endemo-epidemic illness transmitted to man by rodents (Calomys musculinus), which produces a 10-30 % of mortality in non-treated patients. At the moment, there is a vaccine made with the attenuated strain “Candid 1” but it is not manufactured in our country and the doses available are scarce regarding the quantity of people at risk. In order to find an antiviral agent, considering the existing evidence of antiviral activity of NDGA, we conducted an “in vitro” assay against Junin virus. The inhibition of replication as a function of the concentrations of the lignan showed that the virus replication was inhibited differently, according to the NDGA (8-17 mg / ml) concentration and type of treatment (pre, simultaneous and post-treatment). All concentrations of NDGA were able to inhibit 100% of Junin virus replication when the compound was added simultaneously with the virus.