Dehydrative synthesis of oxazolidinones from amino alcohols and CO2 was achieved in the presence of alkali metal carbonates such as Cs2CO3 as catalyst. It is noteworthy that 1 atm of CO2 is enough for the reaction to proceed and no special dehydrating agent is required in this system. A mechanstic study showed that the OH of amino alcohol acts as nucleophile and the OH in the carbamic acid moiety is liberated during the cyclization process.