The distribution of constitutive heterochromatin (C-banding) in the genomes of nine species of Felidae, one species of Mustelidae, two species of Procyonidae, one species of Viverridae, one species of Canidae, and one species of Ursidae has been studied. In the chromosomes of several felid species the C-band is apparently absent. A few chromosomes show only telomeric staining in one arm or sometimes in both arms. Centromeric and interstitial distribution of heterochromatin has also been demonstrated in other species of Carnivores, but, in general, the C-banded material in felids is comparatively less in amount, and more weakly staining, than in other mammals. Induction of C-banding patterns in certain carnivore species is rather difficult, probably because of the minimal amount of heterochromatin present.