Coronary artery disease is one the major causes of death in Indonesia. For early diagnosis of the disease, it is deemed necessary to visualize the myocardium blood flow perfusion. 99mTc-MIBI labeled compound is one of the agent that could be used for such purpose. The labeling of MIBI with technetium-99m under some variations of several parameters has been carried out. The labeling efficiency was determined by counting the radiochemical purity using ITLC-SG 60 thin layer chromatography using two kinds of solvents, i.e. methanol and 0.9% NaCl solutions. The optimum labeling condition was achieved at the pH = 5.5 – 6.0, 1 mg of [Cu(MIBI)4BF4, 0.060 mg SnCl2.2H2O and 10 minutes incubation time in a boiling water bath, gave ± 99% of labeling efficiency. Under the formulation stated above, MIBI dry kit produces could give the radiochemical purity of more than 95%.Key words : metoxy isobutyl isonitril (MIBI), technetium-99m, labeling, myocardiac perfusion imaging.