This paper describes the production and characterization of cationic microparticles based on pullulan and starch for the delivery of nucleic acids.The microparticles were prepared by chemically cross-linkinking of a polymer solution dispersed in organic phase, followed by amination with N, N-diethyl-2-chloroethyl amine hydrochloride or N-glycidyl-N, N-dimethyl-N-methylammonium chloride. The association of desoxyribonucleotide Defibrotide (DFT) with positively charged microparticles was determined. The association capacity and the affinity of microspheres for DFT were investigated as a function of type of polysaccharide, content and basicity of the aminogroups. It was found that the both types of carriers synthetized display a high affinity for Defibrotide due to the high porosity of polysaccharide microspheres. In addition, the in vitro release kinetics from microspheres were determined.