Horizontal, continuous casting of aluminum ingot is discussed with special attention directed to metal supply, mold package, mold lubrication, ingot cooling, and alignment of equipment. In most instances, requirements are more rigorous than with vertical, discontinuous direct chill casting. Horizontal casting necessitates pressure-tight sealing during metal transfer to the mold and compensations for convection and gravity within the mold. Continuous casting requires a constant metal supply and mold equipment capable of producing acceptable ingot for extended periods without ingot quality deterioration.