In order to cytogenetic study were examined six genotypes of Achillea including, A. millefoliumand A. Santolina. In this study were done karyotype determination and determination of the traits contribution in variation. To provide appropriate examined samples, after gathering roots, 0.5 cm root tip was removed and then was carried out pre-treatment and fixation, respectively. After hydrolysis and squash were done imaging and finally were prepared karyotypes. In all genotypes basic chromosome number was x =9. Three genotypes Aligoodarz, Ardabil and Meshkinshar were diploid and Arak, Ilam and Estahban were tetraploid. Based on Stebbins method, Arak and Ilam were classified in Class 1A, Ardabil and Meshkinshar in Class 2A and Aligoodarz and Estahban in Class 1B, respectively. Mean comparisons revealed that the Estahban and Aligoodarz had the lowest and highest the value of the S, L and T respectively. In factor analysis, two factors were explained more than %90.92 of the variance. The first factor was explained %46.65 of variance and was correlated positively with the L/S and the L-S was correlated negatively with %F and the ratio S/L. Therefore, this factor was named as the arm chromosome ratio arm and Huziwara index. The second factor explained %44.27 of variance and was correlated positively with the S, L, T and %RL. Therefore, this factor was named as the chromosome or genome size. Cluster analysis was classified genotypes into two clusters. In statistical analysis employed software' s including, excel (2007), Photoshop (Adobe Photoshop CS2) and SPSS (PASW Statistics18).