A gas cooler for an internal combustion engine is provided that includes a gas duct through which a gas flow supplied to the internal combustion engine can flow in a flow direction, and having a heat exchanger which is inserted into the gas duct through a lateral opening in an insertion direction, wherein a fluid or cooling the gas flow can flow through the heat exchanger, and wherein a first profile which runs in the insertion direction is formed on at least one side of the heat exchanger, which first profile meshes with a second profile provided on the gas duct.