Metaphase chromosome preparations of three male and one female Gorilla gorilla were stained to demonstrate quinacrine, Giemsa, centromeric heterochromatin, and, in one case, reverse-Giemsa bands. A standard karyotype is proposed based on chromosome banding pattern, centromeric index, and length. Three types of variation between homologous chromosomes are described: presence or absence of very bright fluorescence of the short arm or satellite region of acrocentric chromosomes, presence or absence of bright quinacrine bands at the distal ends of chromosome arms, and large differences in the size of the heterochromatic region on each of two biarmed chromosomes. At least half the chromosome pairs show polymorphisms of these types. Satellite associations were scored for each animal. In one case the two smallest pairs of chromosomes were preferentially involved in associations.