The invention provides a process for preparing cyclododecanone. The process includes the steps: a, epoxidizing cyclododecene (CDEN) to epoxycyclododecane (CDAN epoxide), and b, rearranging the CDAN epoxide to CDON to obtain a mixture comprising said CDON and cyclododecane (CDAN). The process is characterized in that CDAN is separated from the CDON-containing mixture and oxidized to CDON.