A mat for covering a cabin floor of a truck comprises a rear section, arranged for fixating the mat to the cabin floor, and a side section, arranged for extending along a door sill of the truck. The side section provides the mat with a declining surface having a lowest level beyond the door sill. The side section comprises a side wall having at least two mounting portions, each mounting portion extending laterally for engaging with a bottom edge of the door sill, to fixate the side wall between the cabin floor and the door sill.