In order to reach a world-wide consensus on the normal range of left (LV) and right ventricular (RV) ejection fraction (EF) at rest and during exercise, pooled data of 1200 normal subjects from 28 leading centres in the field of nuclear cardiology (68% of those contacted) was analysed. Weighted mean normal values for LVEF at rest were 62.3 +/- 6.1% (ISD) with a lower limit of normal of 50% and for RVEF 52.3 +/- 6.2% (N = 365) with a lower limit of normal of 40%. During exercise, LVEF increased in 475 subjects by +8.0 EF% (range 3-15%), a normal increase being accepted to be greater than or equal to 5% over a normal resting value for both LVEF and RVEF. Subgroup analysis of results at rest revealed no significant differences regarding selection of normal subjects (based on normal catheterization findings vs. normal volunteers with low probability of disease), age or sex. During exercise, however, significantly larger increases in LVEF measurements were noted for men versus women (P less than 0.01), for normal volunteers versus subjects selected as 'normals' based on a normal coronary angiogram (P less than 0.001) and for younger versus older subjects (P less than 0.001). Data on reproducibility and variability showed that radionuclide angiocardiography can be considered to be a reliable method today. No consensus was found for measurements of regional LV function or wall motion mainly because of differences in methodology used. These normal values may serve as general guidelines for future applications of these techniques but factors which may influence the normal range as defined and discussed in this study should be recognized.