Various methods have been proposed recently to deal with CO₂because it is one of the greenhouse gases causing global warming. These methods include injection of CO₂ into the ground to increase petroleum production, and sequestration of CO₂ into aquifers. High-efficiency, large-sized CO₂ re-injection centrifugal compressors have been developed for the purpose of subterranean sequestration of CO₂. This paper discusses the features of the compressor and its shop test results at full pressure and full load.