Abstract: A novel variable proportioning valve for balanced pressure proportioning systems and variable liquid proportioning system incorporating such a valve. The valve is adjustably operable in a system to proportion or meter two liquids, for example, at constant pre-selected percentages with a resultant substantially constant or fixed ratio of the liquids even under varying flow conditions. The principles can be used with different and additional fluids. The variable proportioning valve incorporates in the body thereof a flow control plug coacting with an outlet port to control net outlet flow, and the plug is capable of having such configurations and sizes whereby relative motion between the valve plug and the port can provide a wide range of flow outputs of different specific characteristics. The valve has a construction permitting ease of disassembly for valve plug removal and replacement for purposes of repair, or for altering the operating characteristics of the valve, and therefore, that of the system.