We applied direct septal echography in transaortic septal myectomy for left ventricular outflow tract obstruction due to hypertrophic obstructive cardiomyopathy and asymmetric septal hypertrophy. A small L-shaped probe was inserted into the right ventricle through a 2-cm incision on the right ventricular outflow tract. The probe was placed directly on the interventricular septum to visualize its actual thickness. It was also helpful to push and expose the septum into a direct field of vision through the aortic annulus. This type of direct septal echography can be useful for the successful performance of transaortic septal myectomy.