The reaction of N-tert-butyl-2-benzothiazolesulphenamide with acetic anhydride catalyzed by acetic acid in a nonpolar solvent has been studied by NMR, GC-MS and EPR techniques. In the catalytic process homolytic decomposition of N-tert-butyl-2-benzothiazolesulphenamid prevails over the heterolytic pathway which is typical for uncatalyzed reaction. Besides the typical products formed during the uncatalyzed reaction, in the acid catalyzed process products formed by recombination of radicals were confirmed by C-13 NMR and mass spectroscopy. In the formation of TBbisBS by homolytic pathway N,N'-dialkylhydrazine radicals and RNH. radicals, produced by decomposition of N,N'-dialkylhydrazine, play probably an important role.