The invention relates to a turbocharger (1) having a wastegate arrangement (6), in which the leakage at the guide of the regulating flap in a multi-stage turbocharger arrangement is reduced. The turbocharger (1) comprises a compressor (2) and a turbine (3). The turbine (3) comprises a turbine housing (4) which has a turbine housing outlet (5), and a wastegate device (6) which has a regulating flap (7). The regulating flap (7) is arranged on a regulating flap shaft (9) which is guided in the turbine housing (4) by means of a bush (8). The bush (8) is provided with an annular groove (11) formed on its inner circumference (10), which annular groove (11) is connected by means of at least one connecting bore (12, 13) to an annular collecting groove (14) which is provided in the turbine housing (3) and which is connected by means of a relief bore (15) to the turbine housing outlet (5).