We have found that virions of herpes simplex virus type 1 have surface receptors capable of binding to the Fc region of immunoglobulin G and have also shown that the previously identified Fc-binding glycoprotein (designated gE) is present in extracts prepared from purified virions. The technique of affinity chromatography was used to detect gE. Two approaches were used to demonstrate the presence of Fc-binding receptors on intact virions. First, it was shown that [125I]-immunoglobulin G, but not [125I]F(ab')2 fragments, cosedimented with virions in sucrose gradients and, second, electron microscopy was done to show that soluble peroxidase-antiperoxidase complexes bound to virions. The use of peroxidase-antiperoxidase complexes also permitted us to demonstrate that Fc-binding receptors from input (parental) virions become incorporated into the surface membranes of infected cells. This occurs presumably as a consequence of fusion between the virion envelope and cell surface membrane.