Q banding of chromosome preparations from chinook salmon revealed heteromorphic quinacrine bright bands on several chromosomes. These bands appear to represent AT-rich heterochromatin, since they are stained darkly with the C-band technique and negatively with chromomycin A3. Most fish examined had consistent heteromorphisms at several of the quinacrine bright bands. The Q band on chromosome 17 was especially polymorphic, varying in size from 25-55% of the length of the chromosome arm. The results from 3 crosses are consistent with Mendelian inheritance of the Q-band markers, suggesting that these markers could be used in genetic comparisons between different populations.