A centrifugal compressor for compressing a fluid comprises a compressor wheel having a plurality of circumferentially spaced blades, and a compressor housing in which the compressor wheel is mounted. The compressor housing includes an inlet duct through which the fluid enters in an axial direction and is led by the inlet duct into the compressor wheel, and a wheel shroud located radially adjacent the tips of the blades. The wheel shroud has a port for bleeding off a portion of air flowing through the compressor. The bleed air enters an annular space, flows forward, and is injected back into the inlet flow through a plurality of circumferentially spaced slots defined through the wheel shroud. The slots are open at a leading edge of the wheel shroud.