Enzyme labelled immunosorbent assays (ELISA) have been developed to detect and quantify foot and mouth disease (FMD) virus using flexible plastic microtitre plates. The methods were successful for the specific detection of FMD virus and were 50 to 100 times more sensitive than the complement fixation test. The application of the ELISA techniques to FMD virus typing and subtyping, and to the assay of antigen concentration during manufacture of vaccines is discussed.