Here we demonstrate the reversible CO₂ capture capacity of polyaniline/multiwalled carbon nanotubes nanocomposite at high pressures for the first time to the best of our knowledge. High CO₂ capture capacity was achieved for nanocomposite, which can be associated to the possible chemical interaction of CO₂ molecules with nanocomposite. This study promotes the investigation of other polymer-carbon composites for CO₂ capture.