This study investigated replacing primary kidney cells with cell lines for virus isolation assays for foot-and-mouth disease virus (FMDV). In test 1, titers in lamb kidney cells, pig kidney cells, and ZZ-R cells were almost equal, while lower titers were found in BHK-21 cells. In test 2, the highest titers were detected in LFBK cells. The study concluded that IBRS-2 and ZZ-R cells were as sensitive as primary cells and could replace them. LFBK cells were found to be more sensitive than primary cells but current LFBK cells have a pestivirus contamination limiting their use. LFBK cells without pestivirus would be the preferred