Studies of the pachytene stage of human meiosis in young adult males show that the principal nucleoli are associated with the terminal chromomeres of certain bivalents. These findings are reconcilable with earlier observations on the principal nucleolar chromosome on the basis of the association of bivalents by their nucleolus-forming regions. The pattern of multiple associations suggests that three long and two short bivalents are capable of forming terminal nucleoli. The evidence suggests that these five bivalents are the five pairs of satellited chromosomes in the human mitotic idiogram.