A lubricating system for an internal combustion engine includes lubricating oil recovery oil passages through which lubricating oil dropping to and dwelling in a bottom portion of a crankcase after lubricating individual portions of an internal combustion engine is fed to a lubricating oil tank through an oil cooler by a recovery pump. Lubricating oil supply oil passages supply the lubricating oil from the lubricating oil tank to the individual portions of the internal combustion engine needing lubrication and cooling through an oil filter by a supply pump. The lubricating system includes a branch passage branched from the lubricating oil recovery oil passage communicating from the oil cooler to the lubricating oil tank. The branch passage supplies the lubricating oil to at least one of the individual portions of the internal combustion engine.