Abstract: A method for injecting carbon dioxide into an oil or gas well. The carbon dioxide is transported to the well site in a tank while maintaining it at a temperature and pressure sufficient to retain the carbon dioxide primarily in a liquid state. The liquid carbon dioxide is drawn off and pumped to an intermediate pressure by a booster pump. To avoid flashing in the line due to the pressure drop as the liquid is withdrawn, a feedback loop between the output of the booster pump and the tank is utilized. A vaporizer is located in the feedback loop for vaporizing the carbon dioxide injected back into the tank. The amount injected is controlled to maintain the tank at a sufficient pressure to avoid flashing in the discharge line. After the booster pump, the remainder of the liquid carbon dioxide is pumped to a higher pressure by a high pressure pump. The high pressure liquid is commingled with other high pressure liquids and pumped down the well.