Methane sulfenic acid (CH3SOH, MSEA) has been suggested in the literature as a possible stable product within the addition channel of the OH-initiated oxidation of dimethyl sulfide. In particular, it has been proposed as one of the thermodynamically feasible products of the reaction of CH3S(OH)CH3 adduct with O2. However, MSEA has never been experimentally observed and a detailed theoretical analysis of all the reaction pathways leading to MSEA formation has never been reported. In this study, the first density functional and ab initio electronic structure calculations are carried out to characterize those reaction channels yielding MSEA. The adduct formed by the reaction of DMS-OH with O2 (CH3S(O2)(OH)CH3) has been taken as the starting point. On the other hand, a new reaction pathway, which competes with the MSEA formation yielding DMSO instead, is also presented. The kinetic relevance of those different reaction pathways is discussed to assert their contribution to the experimental measurements of the end-products of DMS-OH-initiated oxidation.