The sensitivity of two different types of cells to bovine herpesvirus type 4 (BHV-4) was compared by median tissue culture infectious dose (TCID 50) assays. The bovine arterial endothelial (BAE) cell culture derived from bovine carotid arteries was 100–1000 times more sensitive to two strains of BHV-4, Movar 33 63 and DN 599, than Madin Darby bovine kidney (MDBK) cell line commonly used for the propagation of these viruses. BAE cell cultures infected with BHV-4 displayed cytopathic effects (CPE) earlier and more prominently than the MDBK cells infected with the same viruses. BAE cells were also more sensitive than MDBK cells in conventional plaque assays in that the former developed well characterized and easily recognized plaques after infection with the viruses. BAE cells, which are proved to be exceptionally susceptible to BHV-4, can be used in the detection and quantitation of BHV-4.