From environmental and economic standpoints, molecular oxygen represents the ideal oxidant for chemical transformations. It is readily available, inexpensive (particularly if used without separation from air) and environmentally benign. However, more expensive and/or hazardous oxidants are often employed in homogeneous metal-catalyzed oxidation reactions. In fact, typically organometallic chemists don’t even let their compounds “see” molecular oxygen, using special equipment and procedures to rigorously protect their compounds from the air. Unfortunately, this deliberate exclusion of air has resulted in a lack of understanding of exactly how transition metal organometallic complexes react with molecular oxygen, which in turn has inhibited efforts to design catalysts for selective aerobic oxidations. Kinetic and mechanistic studies of the reactions of oxygen with various late metal alkyl and hydride complexes will be presented along with our nascent mechanistic understanding of these reactions. The generality of these aerobic oxidation reactions and their potential for incorporation into hydrocarbon functionalization strategies will also be discussed.