The recently discovered G virus (also called either GBV-C or HGV) is transmitted by blood transfusion as well as by sexual intercourse. The global prevalence of GBV-C is high, not only in those groups classically known to be exposed to parenteral risks (i.v. drug users, polytransfused patients), but also in the blood donors population. The diagnosis of active infection lies on the search of GBV-C RNA by Polymerase Chain Reaction whereas that of resolved (past) infection lies on the presence of specific antibodies. Till now, it has not been possible to correlate convincingly the presence of GBV-C RNA with any acute or chronic hepatopathy. On the contrary, a lot of arguments tend to suggest that the GBV-C is not pathogenic for the liver, although some modes of transmission are common with those of other (known and probably not known) hepatotropic viruses. According to the actual knowledge of the consequences of GBV-C infection, it appears as non relevant to instaure a systematic screening of this new virus in blood donors.