The phases of cerium above 5GPa have been studied using angle-dispersive powder diffraction techniques. The phase obtained between 5 and 12GPa at room temperature with filings of Ce has a monoclinic, distorted-fcc structure with four atoms in a C-face-centered unit cell. Heating to 373K for many hours yields the known {alpha}-U phase. With a single cut piece as a sample, the {alpha}-U phase is obtained at room temperature. {copyright} {ital 1997} {ital The American Physical Society}