A chemical process has been developed for the separation of 243Am from 244Cm for use in the production of kilogram quantities of 244Cm. In the process, americium is oxidized to ion in concentrated K2CO3 solution, and K3AmO2(CO3)2 is precipitated; Cm(III) is not oxidized and remains as a soluble complex in the carbonate solution. A study of the variables affecting the separation is reported.