An investigation has been made of the kinetics of oxidation of different mercaptans (ethyl- and butylmercaptans, benzylmercaptan) by molecular sulphur. This reaction is regarded as one of the possible interactions occurring during oxidative conversions of sulphur-containing compounds: It is shown that the oxidation of mercaptans to disulphides is accompanied by secondary reactions leading to a change in its stoichiometry. It is assumed that, parallel to the reduction of sulphur to H2S2, its polymerization occurs with the formation of sulphanes H2Sn. The kinetics of the process obeys a second-order equation: d[RSH]/d tau = -k(eff)([RSH]{[S](0)-N[RSH](0)-[RSH])}. From experimental data, the effective rate constants k(eff) and stoichiometric coefficients N have been calculated. A scheme of the possible reactions is proposed.