A fluid flow meter comprising a housing having a pair of fluid port and defining therebetween a fluid flow path (14); a flexible membrane (35) defining a pair of opposing faces and being mounted in the fluid flow path such that the pair of faces simultaneously define with the housing fluid impermeable seals at at least two different locations along the flow path, the membrane (35) being operative to flex so as to permit passage therepast of discrete quanta of fluid, each having a known volume, apparatus for generating electrical signals corresponding to flexure of the membrane (35); and monitoring apparatus for receiving the electrical signals and thereby determining a fluid flow rate along the flow path.