Pressure regulators for beverage dispensers of the type using a high pressure gas cartridge such a CO2 cartridge. The regulators provide a simple, low cost, easily assembled and reliable regulator of particularly small size, facilitated in part by the fact that the invention allows the use of a diaphragm of a particularly small size without necessitating the use of expensive and bulky diaphragm clamps, such as threaded clamps, yet is able to provide a more than adequate seal at both the inner and outer portions of the diaphragm.