Thermal study (TG, DTA) of the palladium(II) complexes of monoethyl 2-quinolymethylphosphonate (2-mqmp): neutral dihalide adducts Pd(2-mqmp)(2)X-2, ion-pair salt complexes [2-Hmqmp](+)[Pd(2-mqmp)X-3](-)(X = Cl, Br) and chelate dihydrate Pd(2-mqmp-H)(2). 2H(2)O, has been carried out in order to determine decomposition properties of these biologically interesting complex compounds. Thermal decomposition of the complexes occured in two steps: dehalogenation along with ligand deesterification is followed by complex pyrolysis that leads to the residue identified as a mixture of the element, Pd and P2O5. This was confirmed by infrared spectroscopic study. No stable intermediate products, except the corresponding anhydrous complex in the case of chelate compound, were found during thermal decomposition due to the complex nature and the overlap of the degradation processes. The results were compared with those obtained for the complexes of diethyl 2-quinolylmethylphosphonate and discussed with respect to their cytostatic activity.