Cocksfoot (Dactylis glomerata L.) is one of the main perennial grasses that naturally grow in arid to semiarid pastures and rangelands, with a typical Mediterranean climate, in northern and western Iran. Despite its importance, there is a lack of information on the genetic diversity within and among populations. Data on total protein profiles and 14 phenotypic traits, collected on 21 wild cocksfoot populations from seven different origins/sources (Iran, USA, Russia, Estonia, Kyrgyzstan, Netherlands and Spain) were utilized for estimations of genetic diversity. Dendrograms were prepared using cluster analysis based on Nei's similarity coefficients in case of total protein profiles and on squared Euclidean distances in case of phenotypic traits. Clustering pattern, made on the basis of protein analysis data, grouped the accessions differently and gave no clear indication of phenotypic performance or origin/source. Further examination of the different components of genetic variation by analysis of molecular variance indicated that larger proportions of variability existed within populations (88%). The results also showed that comprehensive germplasm collection in major geographic regions and exploitation of the existing variation are required to widen the genetic base and sample the full extent of the available variation in breeding strategies for cocksfoot