The TG and DTG study of areneruthenium(II) derivatives [Ru(arene)Cl2L] (arene = benzene or p-cymene (pMeC(6)H(4)CHMe(2)); L = aniline, diethylamine, dimethylsulfoxide, tetrahydrothiofene or dimethylsulfide) was carried out under a dynamic air atmosphere. The kinetics of the first step of thermal decomposition were evaluated from the dynamic weight loss data by means of Coats-Redfern, MacCallum-Tanner and Horowitz-Metzger methods. The D-n and R-n models were selected as the models best fitting the experimental TG curves. The values of activation energy, E, and frequency factor, A, of the thermal decomposition were calculated.