Abstract: Sensitive and specific enzyme-linked immunosorbent assays which detect Clostridium botulinum neurotoxins serotypes A, B, E, and F in a sample are described. The assay is based upon affinity-purified antibodies directed against the C-fragments of each toxin. These assays demonstrate sensitivity close to that of the mouse bioassay without the use of animals and in a much simpler format than other assays of similar sensitivity.