Abstract: The synthesis and X-ray structural characterization of Pd(DMPA)Cl2 complex, where DMPA= N,N-dimethylaminopropylamine, is reported. The complex crystallizes in the space group P21/c, a =8.8923(4), b =10.9050(5), c =11.5006(7) Å, β =120.00(18)°, V =948.25(8) Å3, Z =4. The palladium centre has a typical square-planar geometry with a tetrahedral distortion. Stoichiometry and stability constants of the complexes formed between [Pd(DMPA)(H2O)2]2+ and some selected DNA constituents and cytsteine are investigated at 25°C and at constant 0.1M ionic strength. The concentration distribution diagrams of the various species formed are evaluated. The equilibrium constants for the displacement of coordinated ligands as inosine by cysteine are calculated. The results are expected to contribute to the chemistry of tumour therapy. [Copyright &y& Elsevier]