This paper deals with a computer-aided study of the associations between acrocentric chromosomes as well as between those other chromosomes which in our investigations were revealed to be significantly closer to each other than random. The chromosome pairs were identified by a trypsin-banding technique. The method used has been elaborated previously with the specific aim of determining associations in a manner that avoids all subjective criteria. The tendency for association between homologous chromosomes is in decreasing order: 21 and 13 greater than 1 greater than 14, 18 and 19 greater than 17. Among the nonhomologous acrocentric chromosomes the significant tendencies for associations are between D-D: 13-14 greater than 13-15 greater than 14-15; between D-G: 13-21 greater than 14-21 greater than 13-22 greater than 15-22. The implication of the different tendencies to associate are dicussed in terms of aetiology of numerical and structural chromosome abnormalities.