In this study we have used a method enabling associations between acrocentrics to be determined without recourse to any subjective measurements. By this method, with computer assistance, we were able to investigate the number and probability of occurrence of different types of acrocentric associations (D-D, G-G, D-G) in human male and female spread metaphases. The number of associations per cell are, in ascending order: G-G = 0.28; D-D = 0.37; D-G = 0.91. Their probability of occurrence per 100 cells is, in ascending order: D-D = 2.45; D-G = 3.82; G-G = 4.64. The results show that, on a per cell basis, the most numerous associations are between D and G chromosomes (D-G) because of the greater number of combinations possible. But in terms of chromosome pairwise associations, the clearest probability, or trend, to association seems to be within group G (G-G).