Mitotic chromosomes of rice, Oryza sativa L. (2n=24), were all identified by a newly developed technique. A new technique of cell suspending and flame-drying made chromosomes possible to be well flattened and spreaded. Tissue treatment with KCl and enzyme caused segmental differentiation in chromosome stainability with Giemsa. All chromosomes were able to be identified in a single prometaphase nucleus by individual characteristics. Twelve pairs of chromosomes were gradually different in length and composed of 5 metacentrics, 5 sub-metacentrics and 2 sub-telocentrics including a satellited pair.