A flood control valve assembly designed to be removably mounted within the outer or exposed end of a vertically or horizontally oriented drain pipe and structured to allow water to enter the drain pipe in the conventional fashion but prevent water from issuing from the open, outer end of the drain pipe such as during heavy rain and/or flood conditions. The valve assembly includes a tubular housing having a hollow interior and oppositely disposed open ends which define a path of liquid flow through the housing. The housing is removably secured on the interior of the drain pipe immediately adjacent to the open end thereof and further includes a buoyant material valve member movably mounted within the housing and being positionable into an out of a closed position relative to a valve seat secured adjacent to the outer end of the housing dependent upon the direction of water flow through the housing.