Background: Grade 1 diastolic dysfunction (DD) is a spectrum of a variety of conditions. Objectives: The aim of this study was to demonstrate the usefulness of preload alterations by leg raise in further stratifying diastolic dysfunction in patients with impaired relaxation. Methods: Of the consecutive 1192 patients who underwent diastolic stress echo, 154 patients with abnormal left ventricular (LV) relaxation on Doppler mitral inflow (early (E) / late (A) mitral inflow velocity <0.75 or deceleration time > 240 ms) were enrolled after exclusion of patients with LV ejection fractions less than 50%, a previous history of ischemic heart disease, inducible regional wall motion abnormality, valvular or myocardial disease, or any other volume overloading diseases. After resting evaluation, echo-Doppler measurements were performed during passive leg elevation and symptom-limited graded bicycle exercise. Results: Patients were divided into two groups according to resting E/E���: Group I (E/E���<15) and II (E/E������15, n=23). Group I subjects were further subdivided into IA (persistent E/E��� <15, n=112) and IB (change to E/E������15, n=19) according to response to leg elevation. Group II had lower systolic (S���), early (E���), and late (A���) diastolic annular velocity, and diastolic reserve index to exercise (E���x��E���50W) and higher LV elastance index (E/E���/stroke volume) than that of group IA, however there was no significant difference compared to group IB. Group IB had more female predominance, older age, lower E���, higher diastolic elastance index, and higher E/E��� at 25W and 50W exercise accompanied by lower exercise capacity compared to group IA. Conclusions: Preload augmentation by leg elevation might provide additional information in triaging patients with grade 1 DD.