An oil sump for an internal combustion engine, having at least a monolithic concave member defining a vessel for containing lubricating oil and defined at the top by a peripheral edge securable to a block of the engine; and an oil intake pipe integral in one piece with the sump; wherein the oil intake pipe projects inside the vessel by opposite ends, a first located at a bottom wall of the concave member, and a second substantially flush with the peripheral edge; the oil intake pipe being formed as a separate member from the concave member, and being fixed integrally to the concave member by the first end, at a given distance from the bottom wall, and by an intermediate portion; and the second end of the oil intake pipe having a fast-fit fitting projecting beyond the peripheral edge.