The late prophase orientation of chromosomes is a carryover from late telo phase orientation (Carlson 1956). This is apparently maintained by means of the centromeres, which appear to be attached within a limited region of the nucleus throughout telophase, interphase and prophase (DuPraw 1970, Avivi and Feldman 1980, Lavania and Sharma 1981). Very little is known about the arrangement of centromeres in an interphase nucleus, owing to the inherent technical difficulty to recognize the centromeres at interphase under light or electron microscope. In Lathyrus sphaericus, C-bands as detected by Giemsa banding have been found to be present mainly in centromeric region as thick blocks of C-heterochromation. An additional very thin band is also observed in satellited regions of the nucleolar pair (Lavania and Sharma 1980a). Thus Lathyrus sphaericus provides a suitable material for the study of arrangement, orientation and behaviour of centromeres during cell division cycle.