Abstract: Disclosed is a foundation vent that provides air ventilation and flood relief for an enclosed area. A screen is included to prevent items such as insects, small animals, debris, and organic matter, including buoyant materials due to a flood, from entering the enclosed area. A removable screen and exterior screen stop allow the owner to easily inspect, maintain, clean, and repair the foundation vent. The foundation vent is also designed as a non-engineered, non-mechanical opening, which allows the air and flood water ratings of the foundation vent to be based upon the actual net clear open area. Such design eliminates the need for a vapor barrier and/or specialized structural engineering of the foundation. The dual operation of the foundation vent as a flood grate also allows rising flood water to penetrate and recede from the enclosed area, which equalizes the hydrostatic pressure on either side of the foundation wall.