This study describes the sequence of centromere separation in the Chinese hamster genome and the lack of any effect of Colcemid on this sequence. Analysis of bone marrow cells using sequential Giemsa staining and Q-banding established the sequence of centromere separation in cells derived from four Colcemid-treated and three untreated animals. Treatment of the data by use of the ANOVA test showed that the sequences established in the Colcemidtreated group did not differ from those in the untreated animals. The sequence of centromere separation in the Chinese hamster, as expressed by the pooled data from all seven animals, is chromosomes 1 and 2, followed by 3, 4, X, Y, 8, 9, 10, 5, 6, and 7.