Onion is one of the important strategic crop plants of a highly valuable nutritional food source, consumed almost around the whole world. Thus, the genetically oriented studies around the plant are valuable and inevitable. For a following of these studies, some onion masses from various regions throughout Iran, including: Kashan-White, Azarshahr-Red, Isfahan-Dorcheh, Ghom-White, Zanjan-Gholigheseh, Yasouj-Local, Herssin, Nishabour-Ishaghabad, Yazd-Abarkoh, Ramhormoz against two important commercial varieties, Texas-Early-Grano, and Yellow-Sweet-Spanish were taken into consideration. The obtained results were Arc Signed and, then subjected to DMRT-analysis and as well to cluster analysis according to Ward’s Minimum Variance Method, using the cluster procedure of SAS computer software. The base chromosome numbers were=8 for the studied masses in which number of chromosomes, Length of the longest chromosome, length of the shortest chromosome, longest/shortest length ratio, average of long arm/short arm ratio, as well as the average of chromosome ratios were recorded. The types of chromosomes were found to be Meta-Centric, Sub-Meta-Centric and sub-Telo-Centric. A comparison of the relative length of the shortest chromosome (S %) showed that whereas Kashan-White and Ramhormoz masses, had the more symmetric karyotype respectively, Azarshahr-Red and Herssin were respectively of the lesser symmetric karyotype. A comparison of Differences in Relative Length (DRL) revealed that, Kashan-White and Herssin masses are of the more symmetric karyotype respectively, while Ramhormoz and Texase-Erly-Grano are respectively of a lesser symmetric karyotype. Also, in this study it was shown that Isfahan-Dorcheh, Kashan-White, Zanjan-Gholigheseh, Yasouj-Local, Ramhormoz and Nishabour-Ishaghabad masses carry, Micro Satellites that are similar to those in Texas-Early-Grano masses’ and Yazd-Abarkoh, Ghom-White, Herssin and Azarshahr-Red masses possess, Macro Satellites similar to those in Yellow-Sweet-Spanish masses. According to the dispersion diagram, based on A1 (Intra Asymmetry Chromosomal Index) and A2 (Inter Asymmetry Chromosomal Index), the masses were grouped into two distinct classes, as in confirmation with the results of Cluster Analysis.