The invention concerns uranium-chelating peptides as well as their uses for decontaminating soils and water, and for detecting and treating people contaminated by uranium. Said peptides have a helix-loop-helix type structure comprising the sequence of a calmodulin loop including at least one mutation of neutral residues selected from the group consisting of S, T, C, H, Y, N and Q, of one, two or three residues of at least one of the four calmodulin calcium binding sites: site I: residues selected among D20, D22 and D24 residues; site II: residues selected among D56, D58 and N60 residues; site III: residues selected among D93, D95 and N97 residues; site IV: residues selected among D129, D131 and D133 residues; said positions being indicated with reference to the human calmodulin sequence.