Seventy landrace accessions and eleven genotypes were used for morphological and ISSRrndiversity study. The plant materials were grown in a simple lattice design of two replications forrnmorphological diversity study at Sinana Agricultural Research Center. Ten plants were selectedrnrandomly from each accession/genotype and marked before flowering. Morphological data werernrecorded from all selected plants on eleven traits. DNA was extracted from a bulk sample of fivernplants using a triple CTAB extraction technique. Molecular data were generated using four ISSRrnprimers. ANOVA of morphological data indicated significant differences among the plantrnmaterials. Estimates of phenotypic and genotypic coefficients of variation showed widerrnvariability within and between the landrace populations and between landraces and exoticrngenotypes for different morphological characters. Morphological dissimilarity between thernpopulations ranged from 0.0519 to 0.73. Clustering analysis based on morphological dissimilarityrnmatrix revealed three groups with distinctive morphological traits. The wider phenotypicrnvariability observed encourages improvement activities between the lentils. Molecular analysis,rnon the other hand, showed that exotic genotypes were more diverse compared to the landraces.rnGenetic diversity within the total landrace population (HT) was 0.1734. High AR-based geneticrndiversity (0.1395 â€“ 0.1039) was observed for samples from Gonder, Shewa and Wello. Highrnwithin GR diversity was obtained for samples from NEE and the least for those from SEE. Exoticrngenotypes were more distantly related with samples from Tigray, Gojam and Shewa than tornothers. The genetic distances between populations of Ethiopian lentil landraces ranged fromrn0.2284 â€“ 0.012. Samples from CE were more distantly related to samples of SEE, while therndistance between other GRs was relatively low. Estimates of population differentiation and genernflow were moderately high for ARs. On the other hand, GR-based population differentiation wasrnlow, whereas among GR gene flow was high relative to AR-based population differentiation.rnAMOVA revealed higher within population variation than among population. Cluster analysisrnbased on Diceâ€™s similarity coefficient revealed three groups with distinct molecular profiles bothrnwith and without exotic genotypes. There were highly significant (p < 0.001) correlations, r =rn0.45 and r = 0.26, between morphological and molecular distance matrices, respectively, of thernentire plant materials and landraces separately, implying the validity of both methods forrndiversity study in lentils. Observation of low within AR/population diversity invites furtherrncollection activities, while enriching populations with high genetic diversity.