Abstract: Foot and mouth disease (FMD) viruses which are able to grow on BHK-21 cells in suspension are described herein. The new viruses are recombinant chimeric viruses formed by replacing the outer capsid coding region of a first FMDV strain, which has previously been shown to be an effective vaccine strain, with the outer capsid coding region of a second FMDV strain. The outer capsid coding region of the second FMDV strain is also modified to introduce a heparan sulphate proteoglycan (HSPG) binding site. The chimeric viruses are then used as seed viruses in the production of inactivated vaccine antigens which have been tailored for specific outbreak situations or locality. The invention also relates to the product of expression of the chimeric FMD viruses and to uses therefor, such as to form antigenic, immunological or vaccine compositions for prevention of FMD.