At pachytene, approximately 35% of the analyzable cells of Ricinus communis, variety Gamadon, exhibit H- and cross-shaped configurations of four chromosomes. Such “interchromosomal associations” involving chromosomes F and G occur in about 19% or the analyzable cells. The centromeres of chromosomes E and G assume a central possition in most of these configurations. A comparative study of the macrochromomere pattern of the free chromosome pairs E and G indicates a morphological similarity between two groups of three macrochromomeres located in the long arm of chromosome E and the short arm of chromosome G, adjacent to the centromeres.At diakinesis and metaphase I interchromosomal associations consist of true configurations of four as well as loose associations of pairs. The di-akinesis interchromosomal associations involving the nucleolus chromosome E and one other (presumably G) do not normally consist of true configurations of four chromosomes linked by chiasmata, but only of secondarily associated pairs. There is a correspondence between the frequency of interchromosomal associations involving chromosomes E and G at pachytene and that at diakinesis involving chromosome E and one other chromosome.In Ricinus, secondary association involving different chromosome pairs can be thought of as the consequence of either or both of the following zygotene-pachytene processes; 1) fusion of the chromosomes at the centro-meres; 2) the exchange of portions of pairings strands affecting two of the four chromosomes involved in interchromosomal association without the for-mation of chiasmata in the regions of interchromosomal contact.