Abstract: A deflector for an electromagnetic retarder including a rotary shaft with a fan for circulating a cooling gas to the induction coils which are intended, upon command, to generate Foucault currents in a stator surrounding the rotary shaft and the induction coils. The inventive deflector (1) includes a body (2) which is provided with at least one return face (3), known as the radial return face, which is intended to release the gas radially from the retarder, said body (2) being shaped such that the deflector (1) can be disposed non-rotatably and coaxially in relation to the shaft of the retarder.