Background: Balloon aortic valvuloplasty (BAV) is resurging as a bridge treatment in patients with severe aortic stenosis (AS) with a dissemination of transcatheter aortic valve implantation. However, the significantly high periprocedural mortality and complication rates still limit the indications of BAV. Further efforts are needed to improve the safety and efficacy of BAV. Methods and Results: We retrospectively investigated the safety and efficacy of simultaneous biplane mode of 3-dimensional transesophageal echocardiography (biplane-TEE) guided antegrade transseptal multiple-inflation BAV, with gradual upsizing of the balloon, by enrolling 20 consecutive AS patients who underwent BAV. The median age was 83 years, and there were 6 male patients (30.0%). The clinical frailty scale was 4, and the Society of Thoracic Surgeon score was 14.5%, The balloon was inflated at a median of 18 times, which improved the mean aortic valve pressure gradient from 43.0 to 15.2 mmHg (P<0.001). We safely performed BAV in all patients, without periprocedural death or symptomatic stroke, although asymptomatic stroke was detected in 8 patients (42.1%) on diffusion-weighted magnetic resonance imaging. Kaplan-Meier estimates showed that the survival rate was 84.0% and cardiovascular death-free survival was 88.9% at 1-year. Conclusions: Biplane-TEE guided antegrade multiple-inflation BAV might have the potential to improve periprocedural survival without increasing complications, compared with conventional retrograde BAV in patients with severe AS.