https://onlinelibrary.wiley.com/toc/15213935/0/0Carbon dioxide (CO₂)‐switchable composite nanogels consisting of biopolymer chitosan and synthetic polymer poly [N‐(3‐(dimethylamino) propyl) methacrylamide] are fabricated by soap‐free emulsion polymerization. Introduction of chitosan in nanogels remarkably enhances their CO₂ sensitivity. Purging with CO₂, the nanogel latex becomes clear gradually from the original creamy white. While purging with N₂, the nanogel solution returns to the original latex state.