BACKGROUND AND OBJECTIVES: Reverse redistribution pattern (RRP), that is defined as the worsening of the perfusion defect at rest image, can be observed in 99mTC-sestamibi (methoxy isobutyl isonitrile) myocardial scan with standard stress-rest protocol. This study was prepared to evaluate the prevalence and clinical characteristics of RRP in stress 99mTc-sestamibi myocardial scan. MATERIALS AND METHODS: We retrospectively reviewed 1304 images of 99mTC-sestamibi myocardial perfusion scan performed between January 1995 and June 1997, and scintigraphic findings were compared with clinical and angiographic data. RESULTS: The prevalence of RRP was 5.2%(68 of 1,304). RRP was noted in 6.0% (41 of 679) of the adenosine study and 4.3% (27 of 625) of the exercise study. The mean coronary artery stenosis at RRP territory was 51.5+/-38.9%. However, normal coronary artery at RRP territory was noted in 45.8% (11 of 24). There was no significant differences in luminal narrowing of coronary arteries, TIMI flow grade and LV wall motion between the patient with RRP positive and RRP negative at the infarct related artery territory. CONCLUSION: Reverse redistribution pattern on 99mTC-sestamibi myocardial SPECT does not seem to indicate the presence of significant coronary artery disease or patency of the infarct related arteries in the patients with acute MI.