Low-gradient (LG), low-flow (LF), severe aortic stenosis (AS) with preserved ejection fraction (PEF) is considered by some authors as an advanced form of AS associated with very poor outcome. The aim of this Doppler echocardiographic study was to investigate changes over time in the hemodynamic severity of LG/LF AS with PEF. We retrospectively identified in 2 academic centers 59 patients who had 2 Doppler echocardiographic examinations without an intervening event. After a median follow-up of 2 (interquartile range [IQR] 1.3 to 3.5) years, progression was observed with increase in mean Doppler gradient (MDG; from 27 [23 to 32] to 37 [28 to 44] mm Hg; p <0.001), peak aortic jet velocity (from 330 [314 to 366] to 373 [344 to 423] cm/s; p <0.001), and decrease in aortic valve area (AVA; from 0.73 [0.63 to 0.92] to 0.64 [0.56 to 0.75] cm²; p = 0.001). Annual rates were, respectively, 8 mm Hg/year, 36 cm/s/year, and −0.04 cm²/year. EF decreased from 62% (55% to 69%) to 58% (51% to 65%), p = 0.001. At follow-up, MDG increase was observed in 51 patients (86%), and 24 patients (41%) acquired the features of classical high-gradient (HG) severe AS (MDG ≥40 mm Hg and peak aortic jet velocity ≥400 cm/s). There were no differences as regard to baseline hemodynamic parameters between patients who displayed ≥5 mm Hg MDG increase and those in whom such increase was not observed. In conclusion, most patients with LG/LF AS with PEF exhibit over time increase in MDG and decrease in AVA with slight EF impairment. This result suggests that LG/LF AS with PEF is an intermediate stage between moderate AS and HG AS rather than an advanced form of the disease.