The new layer chalcogenides KCuFeS2 and KCuFeSe2 have been prepared from the copper iron chalcogenide and potassium carbonate. Both phases crystallize with tetragonal symmetry , in the space group I4/mmm (Nr 139) with a=383.7 (1) pm , c=1338.4 (4) pm and a=397.9 (2) pm , c=1378.7 (54) pm respectively in the ThCr2Si2-type structure. The chalcogen atoms form bidimensional layers of edge sharing pyramids. Copper and iron are statistically distributed in tetrahedral sites. The potassium ions are placed in cubic sites between the layers.