The beta-toxin gene from Clostridium perfringens type C was cloned and expressed as a glutathione S-transferase fusion protein in Escherichia coli. The DNA sequence was determined and compared to the type B sequence. Two nucleotide differences were found in the protein coding sequence, resulting in one amino acid difference between the two proteins. The purified beta-toxin fusion protein is not toxic in mice, but rabbit antiserum raised against it neutralises the toxic effect of C. perfringens type C culture filtrate in mice.