99mTc-tetrofosmin is a lipophilic, cationic diphosphine which has been developed for myocardial imaging. We examined 9 patients with ischemic heart disease including 3 angina pectoris (AP), 4 old myocardial infarction (OMI), 1 AP with OMI and 1 syndrome X. One patient was examined before and after operation. 370 MBq of 99mTc-tetrofosmin was injected during exercise and 740 MBq at rest. And 74 MBq of 201Tl myocardial exercise and redistribution scintigraphy was also performed to compare with 99mTc-tetrofosmin myocardial scintigraphy. SPECT, multiple gated SPECT and anterior planar images were obtained in all cases. We calculated percent wall thickening (%WT) using multiple gated SPECT images. There was a decreased lung uptake in 99mTc-tetrofosmin planar images compared to 201Tl myocardial scintigraphy. Liver and Biliary system uptake in 99mTc-tetrofosmin images was decreased with intake of milk. Segmental comparison of SPECT images showed an agreement in 9/10 of the segment between 201Tl and 99mTc-tetrofosmin. We could obtain excellent quality of multiple gated SPECT images in all patients. We could calculate percent wall thickening (%WT) in all patients. We conclude that 99mTc-tetrofosmin myocardial scintigraphy should provide usefulness for detection of ischemic myocardium as same as 201Tl myocardial scintigraphy, although the biologic characteristics of two agents were different. These data and excellent quality of multiple gated SPECT images suggest that 99mTc-tetrofosmin is a new 99mTc agent for evaluation of patients with ischemic heart disease.