Centromere-center distances were analyzed in 50 normal female and 100 normal male metaphases. Compared with the random distribution of all chromosomes, chromosome pair 6 had a significantly different distribution in both female and male metaphases. Moreover, a significant peripheral location of chromosome pairs 4 and 5 and a significant central location of chromosome pairs 13, 15, 21, and 22 were found in male metaphases. But no specific peripheral location could be assigned to the X or Y chromosomes. No inter- nor intraindividual differences or sex-dependent variation in centromere-center distances were observed. Variance analyses demonstrated consistent centromere-center distances in normal human metaphases obtained from individuals of the same age. The constancy of these chromosome distributions may correlate with chromosome duplication pattern, chromosome length, and chromosome structure.