This article analyses the reactions of organometallic reagents with carbon monoxide. As many reviews have been published on the metal carbonyl-assisted carbonylation of organic compounds, this review is concerned only with the direct carbonylation of organometallic reagents with carbon monoxide. Mechanistic aspects of the reactions are not discussed in detail. The reactions are discussed according to the organometallic reagent employed 1. Organolithium Reagents 2. Organomagnesium Compounds 3. Organoboranes 4. Organomercurials 5. Organopalladium Compounds 6. Other Organometallic Reagents