Karyotype analysis of 7 species of Echinopsis of the tribe Cereeae of the family Cactaceae revealed significant interspecific variations. The diploid chromosome number 2n=22 was found in all the studied species. Significant variation in total genomic chromosome length, volume and in 4C DNA content in the root tip cells was recorded. The nuclear DNA content varied from 7.353 pg in E. werdermanii to 10.353 pg in E. eyerisii; new record on genome size. Correlation coefficient analysis confirm the significant correlation between chromosome volume and nuclear DNA content. Interspecific variation evident in the structural alteration of the somatic chromosome along with genome size suggested the species-specific variations of genomic organization through the variation in repetitive DNA sequences of the species.