The frequencies and geographical distribution of B chromosomes on 15 strains of rye(Secale cereale L.) collected from various localities in Korea were investigated. All of the 15 strains of rye investigated were found to have B chromosomes, and the frequencies of B chromosomes ranged from 6% to 51% with 20.1% average. Plants with 2Bs seem to be the most stable in populations with B chromosomes. Of 1400 plants examined, one plant was observed to have a deficient-B chromosome in Buyo rye.