Data from microsatellite markers have been extensively used for bothrnin situ and ex situ conservation strategies through determining thernlevel of genetic diversity of natural populations that can widen therngene pool of cultivated plants. Such conservation practices should alsornlie on understanding the between and within population geneticrnvariation and partitioning populations on the basis of geographicrnorigin. Therefore, the objective of this study was to assess the intraspecificrndiversity in Oryza longistaminata and how the variation isrnpartitioned within and between different geographic regions of therneight Oryza longistaminata populations in Ethiopia using simplernsequence repeat markers. The five microsatellite markers in 320rnsamples generated 64 allels that revealed the presence of large amountrnof genetic variability (Ho =0.225; He = 0.768; Na = 7.375; Ne = 6.565rnand P = 0.744). The F-statistics detected by the microsatellite locirnshowed Fst = 0.064 and Fis = 0.743 and there was no population inrnHardy-Weinberg equilibrium. The genetic parameters estimated fromrnthis data indicated that there are high levels of genetic diversity in thernpopulations of O. longistaminata studied and this diversity is higherrnwithin than between populations. Regional partitioning also revealedrnthat most of this diversity is found between populations within regionsrnthan among regions. Among all the populations sampled, fivernpopulations (EG-4 and all Amhara populations) were identified asrnpriorities for conservation strategies and thus, national collection andrnconservation strategies need to consider population and regionalrndifferences.rnKey words or phrases: genetic variability, microsatellites, Molecularrnmarkers, Oryza longistaminata, populations and simple sequencernrepeats.