Summary Cytogenetic analysis of 12 populations of 10 Amaranthus L. species and varieties revealed the presence of 2nϭ32 and 34 chromosome number in them. The species studied showed a normal meiosis forming manly bivalents in metaphase of meiosis I. A post pachytene diffuse stage occurred in all the species possibly as a means of adaptation to adverse environmental conditions. ANOVA test revealed significant differences in relative cytogenetic characteristics including chiasma frequency and distribution as well as chromosome pairing among the studied species, indicating their genomic differences. Grouping of the species based on cytogenetic data almost agrees with the clustering of Amaranthus species based on morphological and protein data.