X ray powder patterns have been obtained on MnF2 at 35 kbar and 200¿C. Original rutile type patterns have disappeared completely, and the new patterns may be indexed as tetragonal with a=5.122¿0.002 ¿ and c=5.256¿0.003 ¿. Intensity measurements are best fit by the space group (P42m) but do not preclude other space groups of still lower symmetry. This structure is a distortion of the fluorite type (Fm3m). The density 4.478 is some 14% greater than that of the rutile type.