The interaction with phospholipid bilayers of two synthetic peptides with sequences corresponding to a segment next to the native N-terminus and an internal region of the E2 structural hepatitis G virus (HGV⁄GBV-C) protein [E2(7–26) and E2(279–298), respectively] has been characterized. Both peptides are water soluble but associate spontaneously with bilayers, showing higher affinity for anionic than zwitterionic membranes.