A method is described for iodination of 2,6-dimethylacetanilide and preparation of a corresponding IDA-derivative for labelling with99mTc. The iodination is achieved by electrophylic substitution reaction of chloroacetanilide in the presence of ferroiodide and copperchloride as catalyst. The product of the reaction is 4-iodine-2,6-dimethylacetanilide. The synthesis yield is 70–76%. The synthetized compound was identified by IR an NMR spectroscopy. The insertion of an iodine atom in the benzene ring of this compound decreases its urinary excretion an hastens the liver and blood clearance. The urinary excretion of 2,6-dimethyl IDA (8.5%) decreases to a value of 1.8% of the injected dose when the iodinated preparate is used.