Abstract: A multiple fluid proportioning and dispensing apparatus particularly well suited to dispense two fluids to be mixed together in predetermined ratios and capable of handling highly abrasive substances. The apparatus is characterized by the arrangement of two variable volume chambers operatively connected to the respective fluid sources and to respective piston and cylinder arrangements. At least one of the piston and cylinder arrangements include a piston stroke length adjustment sleeve to permit varying the delivered volume of one fluid relative to the other to and include control valve arrangements to automatically dispense the mixture of the predetermined proportions in an efficient manner.