Fluid flow control valve, the valve comprising a valve housing (10) provided with a flow channel (12), which in direction from the inlet section to the outlet section, comprises a substantially conical inlet (13), a valve seat (14), and a diffuser (15) at the outlet section, which transfers into a flow channel (16). A needle-shaped spindle (11) is arranged axially movable within the flow channel (12) and exhibits a largest diameter DN. The inlet (13) exhibits a first conical inlet section (13') having an angle α1 of 15° with the longitudinal axis of the flow channel (12), and a second inlet section (13") with a radius of curvature R2 equal to 5.7 times the diameter DN of the spindle (11). The diffuser (15) is conical having an increasing cross-section in the flow direction by an angle α2 of 30° with the longitudinal axis in the flow channel (12). The design of the valve produces minimum erosion at the inlet section, and minimum cavitation and erosion in the diffuser section (15).