A chain cleaner capable of cleaning dirt and debris from the roller chain of a chain driven vehicle is provided. The chain cleaner is a polymer sheet. The sheet has a leading and a trailing edge, upper and lower surfaces, and a bilateral axis defining a chain line. The chain line extends from the leading to the trailing edge. A clear slot is positioned in the sheet adjacent to the trailing edge. The slot has a predetermined height and width which is at least equal to a respective height and width of the chain to be cleaned. The chain is thereby capable of biased directional travel against the lower and upper surfaces and through the slot, along the chain line when operating the chain drive of the vehicle. The chain cleaner includes an assembly for attaching the sheet to the vehicle adjacent to the leading edge.