Abstract: The charge property of a new potential myocardial perfusion imaging agent 99 Tc mN MIBI is confirmed by electrophoresis and cationic resin exchange experiments. At the same time,the charge property of 99 Tc mN MIBI is compared with that of 99 Tc m MIBI. The results of electrophoresis experiments indicate that the 99 Tc mN MIBI complex(about 75.63 %)does not migrate from the origin point at all conditions,while the 99 Tc m MIBI complex(about 96.72 %) migrates toward negative pole.In the cationic resin exchange experiments the linear slopes of lg D pH for 99 Tc mN MIBI and 99 Tc m MIBI are 0.04 and 0.99,respectively. The results obtained show that the 99 Tc mN MIBI complex is neutral,while the known 99 Tc m MIBI complex is charged with positive mono valence.