Oral type 1 and genital type 2 Herpesvirus hominis (HVH) strains demonstrate distinctive biological properties in primary chick embryo cells (PCE) cultivated in microtest plates. With this procedure four reference strains of known types and 106 clinical isolates were differentiated as type 1 or 2. The type 1 strains showed low efficiency of infection and either no cytopathic effect (CPE) or only an incomplete CPE characterized by uniform thinning of the cell sheet in test wells. Type 2 strains had a high efficiency of infection and with CPE characterized by patchy plaque-like lesions readily distinguished from CPE of type 1 strains. A 96% correlation (27/28) between the PCE microtyping and kinetic neutralization tests and a 94% correlation (60/64) between the PCE microtyping and immunofluorescence test was obtained. The microplate PCE test is a simple, clear-cut, and reliable procedure for the typing of HVH.