A thermal analysis study of some new organotellurium compounds of the type (AB-ArTeX3, where A = CH3CONH, B = CH3, Br,. NO2 and X = Cl, Br) is reported. These compounds have been prepared by the mercuration route, which included the substitution of the tellurium trihalide group in the ortho position instead of the mercury chloride group. The new compounds have been investigated by TG and a 3-step decomposition process which, apparently, yield tellurium dihalide as an intermediate and tellurium dioxide as the final residue.