A simple procedure is described which permits the rapid identification of clinical herpes simplex virus isolates. The test utilizes Staphylococcus aureus to which anti-viral immunoglobulins had been adsorbed. Adherence of the antibody-coated bacteria to virus-infected cells is readily seen by light microscopy. Indirect immuno-fluorescence and the S aureus adherence reaction were found to be approximately of equal sensitivity for the detection of virus antigens.