Genetic variations were studied for 13 accessions of Lolium multiflorum using cytogenetical traits. Karyotype was prepared for 5 metaphases cells of each accession and the traits of total length (TL), long arm (LA), short arm (SA), arm ratio (AR) and centromer index (CI) were determined by micromeasure software. Six accessions were diploid and seven accessions were tetraploid, the basic chromosome number was x=7, and also three and six satellites were observed for diploid and tetraploid accessions, respectively. The accessions had an asymmetry karyotype, and variations were significant (at 1% level of probability) between accessions for karyotypic characters based on analysis of variance (ANOVA). Results of mean comparison showed that the diploid accessions had higher mean chromosome length than tetraploid accessions. The results of cluster analysis by Ward's method based on the values of intrachromosomal asymmetry index (A1) and interchromosomal asymmetry index (A2) showed that the studied accessions were fallen in three groups. The tetraploid accessions had higher intrachromosomal asymmetry than the diploid accessions. Principal components analysis based on karyotypic traits for accessions showed the first two components captured 84.37% of the total variance. Principal component analysis for grouping accessions based on Scatter plot identified four distinctive groups. پرونده مقاله