A fluid flow regulator in which the fluid flow therethrough is restricted twice, first through a fixed orifice in a slidable piston and then through a variable flow restrictor which is a spring. This spring is axially aligned with and bears against the piston, and fluids issuing from the orifice empties into the interior of the spring, the end of the spring opposite the piston being closed. Fluids thus flow from within the spring through the gaps between its coils and into a chamber surrounding the spring, and from there exits through the outlet of the regulator. The gaps between the spring coils are quite narrow and cause the flow of fluids to be restricted this second time. This restriction is variable since the piston moves as the differential pressure thereacross varies which causes the length of the spring to vary accordingly. This in turn varies the size of the gaps. In this manner, the regulator compensates automatically to provide a fluid flow rate which is substantially constant.