Abstract: A compressor is provided suitable for compressing natural gas from a pressure associated with a residential gas supply to a pressure suitable for an automotive gas tank. The compressor utilizes a par of pneumatic cylinders driven by a hydraulic cylinder to compress the gas in a multi-stage process. Various embodiments are provided with respect to the gas compressor portion and the drive portion. A pressure boost system is also provided which utilizes an internal control valve and internal orifice through the piston of one of the pneumatic cylinders.