An internal combustion engine includes an engine block with at least one cylinder, a cylinder head which is fastened to the cylinder, the outside of the cylinder and the cylinder head including cooling ribs in order to discharge the heat produced during operation of the internal combustion engine, and including an oil pump for conveying the engine oil through oil lines to the parts of the internal combustion engine to be lubricated and to an oil cooler for cooling the engine oil. An effective and even cooling of the internal combustion engine is ensured in such a way that the oil cooler is integrated in the cooling ribs of the internal combustion engine and two mutually separated oil conduit systems are provided in the cylinder head, namely lubricating oil system and a cooling oil system.