Abstract: An arrangement for mixing a first and a second gas flow, for example, an inlet flow with a exhaust gas return flow in a diesel engine, comprising a line (16) for the first flow, an inlet (7) for the second flow in the line (16), in order to achieve the mixing; a streamlined body (8) arranged to be displaced in the longitudinal direction of the line (16) at the inlet (7) in order to achieve a variable venturi effect and in this way a variable suction effect and mixture of the mixed flow; and actuating means for displacing the body forwards and backwards in the line. In order to minimise the need for throttling and the accompanying pressure losses, the streamlined body (8) and the supply part (2) are designed to achieve maximal throttling in the line (16) close to the inlet (7), independently of the position of the body.