Abstract: A system for administering gas to a patient during an endoscopic or medical procedure includes elements for regulating the temperature, pressure, and volumetric flow rate of the gas. A gas source operating with a heated pressure regulator and filter provide a smoothly regulated flow of any medically necessary gas, such as CO.sub.2, to a main body of the gas delivery system. The main body comprises a primary heater for control of the temperature of the gas administered to the patient, a fine pressure regulator for controlling its pressure in a safe manner, and a flow regulator for controlling its volumetric flow rate. Temperature, pressure, and volumetric flow rate indicators allow the physician continuous monitoring of the quantitative status of each of these important physiologic parameters; this data may also be recorded for documentation purposes.