Technetium-99m tetrofosmin (Myoview) has unique properties for myocardial perfusion imaging very early after injection of the tracer. We used a very short same-day rest/stress protocol, to be performed within 2 h and evaluated its diagnostic accuracy. The study included 144 patients from seven Spanish and four Portuguese centres with a diagnosis of uncomplicated coronary artery disease (CAD); 78 patients (54%) had no history of prior myocardial infarction. Patients were injected with </=300 MBq 99mTc-tetrofosmin at rest and </=900 MBq approximately 1 h later at peak exercise. Single-photon emission tomographic (SPET) acquisitions were initiated within 5-30 min post injection. The results were compared with those of coronary angiography (CA). The data of 142 patients were completely evaluable (two with non-evaluable images were excluded). The quality of rest images was excellent or good in 86%, regionally problematic in 7%, poor but well interpretable in 5% and non-evaluable in 2%. The overall sensitivity for the detection of CAD was 93%, the specificity 38% and the accuracy 85%. The localization of defects by SPET in relation to the perfusion territories of stenosed vessels (>/=50%) was achieved with a sensitivity of 64% for the left anterior descending artery, 49% for the left circumflex artery and 86% for the right coronary artery, and an accuracy of 71%, 72% and 73% respectively. Concordance of SPET and CA was 62% for single-vessel disease and 68% for multivessel disease. In conclusion, this Spanish-Portuguese multicentre clinical trial confirmed, in a considerable number of patients who underwent coronary angiography, the feasibility of 99mTc tetrofosmin (Myoview) rest/stress myocardial SPET using a very short protocol (2 h).