Abstract An immunological classification of neurotoxins from North African scorpion species is proposed. Fifteen purified toxins could be divided into three groups, which appears to agree with the classification suggested earlier on the basis of amino acid sequences. Three antitoxins were obtained from rabbits after injection of three pure neurotoxins taken as representatives of the three groups: neurotoxin I and neurotoxin II of Androctonus australis Hector and neurotoxin I of Buthus occitanus tunetanus. These antitoxins only neutralized the toxins belonging to the same group as the antigen. The advantage of such antitoxins is that they can be mixed to neutralize very effectively all the toxins in whole venoms of African scorpions. These mixtures also showed a much higher neutralizing capacity than did any other sera obtained by injecting venoms or telson extracts. For practical reasons, however, the use of neurotoxic fractions obtained after Sephadex G-50 gel filtration chromatography of the venom is recommended for antivenin-producing laboratories. These partially purified toxic fractions, when injected to rabbits, gave rise to more potent antivenins against whole venoms than those presently commercially available.