A high pressure regulator for compressed gas weapons, and in particular for paintball markers, is situated inside a cylindrical regulator housing which is connected to a source of compressed gas. The cylindrical regulator housing comprises an inlet channel which is connected to a supply of high-pressure gas. A first regulator (H) comprises a first piston movably disposed within the regulator housing for regulating pressure in a first expansion chamber. A second regulator (D) comprises a second piston movably disposed within the regulator housing for regulating pressure in a second expansion chamber. The first piston and the second piston are arranged coaxially within the regulator housing. The high pressure regulator is suitable to be mounted in the foregrip of a paintball marker and reduce an inlet pressure of about 850 psi to a first pressure of about 250 psi and a second pressure of about 100 psi.