The binary Ba-Li system was reinvestigated for compositions with less than 80 at. % Li. A new compound, Ba19Li44, stable up to 126 degrees C, was found and structurally characterized. According to single-crystal X-ray diffraction data, the compound crystallizes in a new structure type with a tetragonal unit cell, space group I (4) over bar 2d, a = 16.3911(5) angstrom, c = 32.712(1) angstrom, Z = 4, and V = 8788.7(5) angstrom(3). It can be described as a complicated variant of the chalcopyrite structure. Typical for Li-rich phases, Ba19Li44 contains icosahedron-based polytetrahedral clusters.