Amaranthus species are of underutilized orphan crops grown in tropical and sub-tropical regions of the world. Benin’s most appreciated Amaranthus cruentus L. «local» cultivar is susceptible to saline stress. This study aimed to create genotypes agronomically, at least, as good as the «local» cultivar and useful for further saline tolerance breeding using mutation breeding. The morphological diversity among 19 gamma-irradiated A. cruentus mutant lines and «local» cultivar (control) were investigated, through a randomized complete block design with three replications, using 18 phenotypical traits (12 quantitative and 6 qualitative). The results show that among the six qualitative traits, only terminal inflorescence shape was discriminant. However, permutation analysis of variance revealed significant variability in quantitative traits: leaf width (CV=19%), Branches length (CV=47%), plant height (CV=25%), stem diameter (CV=29%), number of branches (21%) number of leaves (CV=25%). Multivariate analysis of quantitative traits showed the first two principal components contributing to 78.30% of observed variability. Correlation analysis revealed the significance of number of leaves, number of branches, plant height and leaf width for selecting better genotypes for biomass production. Mutant lines L1, L2, L6, L16, L18 and L23 showed high performances for traits cited above and could, therefore, be a good source of genes.