Radiation absorbed doses associated with myocardial perfusion imaging (MPI) using 99mTc-MIBI has been determined at the Radioisotopes Institute of the Abdou Moumouni University. Thirty patients undergoing MPI were scanned and image quantification was done using Mediso Inter View XP® software. The average administrated activities of 99mTc-Sestamibi were 370 MBq (10 mCi) in stress condition and 1110 MBq (30 mCi) in rest condition with one day protocol. The radionuclide activities in the heart, liver, kidneys and urinary bladder were determined using the conjugate view method. The uptake of 99mTc-MIBI in the heart, liver and kidneys were respectively about 2.17% ±0.64, 6.53% ±1.47 and 5% ±0.52, 10 minutes after injection. The cumulative activities for the heart, liver, kidneys and urinary bladder were respectively 21.97 MBq.h, 63.11 MBq.h, 36.61 MBq.h, 79.48 MBq.h for the stress and 68.23 MBq.h, 239.79 MBq.h, 101.69 MBq.h and 223.1 MBq.hin the rest conditions. The organs absorbed doses in this study were 3.06 mGy for kidneys, 0.75 mGy for liver, 0.75 mGy for the heart, and 20.46mGy for bladder.