The flood vent of the invention provides a frame configured for installation in a concrete block foundation wall in place of a single block. The frame includes an angularly oriented window. A gate is pivotally mounted at an upper end thereof within the frame to rest against the window, causing the gate to reside at an angle and be held closed by gravity. A float is mounted to the gate and positioned at rest below the lower edge of the frame to cause the gate to pivot toward an open position when flood water rises to a level approaching the wall opening.