The problem of a possible clustering of human chromosomes containing genes with related functions was examined in the interphase nucleus of lymphocytes by a statistical comparison of distances between chromosomes containing such functionally related genes with all sets of chromosome distances. The gene locus assignments were taken from a recent review (McKusick 1982); the chromosomal distances were those estimated by Hager et al. (1982) from the frequencies of reunion figures between specific chromosomes as observed in chromosome instability syndromes (Fanconi anemia, Bloom syndrome) and after treatment with Trenimon. Chromosomal distances had been estimated by multidimensional scaling. There was no general tendency for closer location of chromosomes containing genes with related function. A few such chromosomes do show below average distances but this could easily be a chance result.