The physical properties of Pb2+impurities in the perovskite-like lattice of KMgF3are very similar to those of (ns)2ions in alkali halides. The impurity inhomogeneous distribution leads to high dopant levels in the bottom region of the crystals, with a segregation coefficient equal to 0. 020. The optical features of the 336 nm emission support its attribution to luminescence of Pb2+ions from the relaxed excited B state.