Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyses the incorporation of inorganic CO(2) into the organic molecules of life. Rubisco is extremely inefficient as a catalyst and its carboxylase activity is compromised by numerous side-reactions including oxygenation of its sugar phosphate substrate by atmospheric O(2). The reduction in the catalytic efficiency as a result of these processes has implications for crop yield, nitrogen and water usage, and for the global carbon cycle. Several aspects of Rubisco including its complex biosynthesis and multi-step catalytic reaction are subject to tight control involving light, cellular metabolites, and molecular chaperones. Numerous high-resolution crystal structures of different forms of Rubisco are now available, including structures of mutant enzymes. These provide a molecular framework for the understanding of these processes at the molecular level.