The characteristic features of methanethiol synthesis from dimethyl sulfide and H(2)S in the presence of Al(2)O(3) at atmospheric pressure and T = 320-500A degrees C have been studied. It has been shown that the yield of methanethiol increases with an increase in the temperature, the H(2)S-to-dimethyl sulfide ratio, and the contact time, attaining equilibrium values. The methanethiol formation rate is proportional to the dimethyl sulfide partial pressure raised to a power of 0.4 and the H(2)S partial pressure raised to a power of 0.8. An increase in the specific surface area and the volume of transport pores and a decrease in the particle sizes of Al(2)O(3) facilitate the augmentation of the catalyst activity in methanethiol formation. At T similar to 400A degrees C, a low H(2)S concentration, and a long contact time, the side reaction of dimethyl sulfide cracking occurs to result in the release of methane and the deposition of sulfur-containing and carbonaceous compounds on the surface, which lower the activity of alumina. The deactivated catalyst can be regenerated by oxidation.