The present invention provides iRNA agent including at least one monomer having the structure shown in formula (I') ##STR00001## wherein: A and B are each independently for each occurrence O, N(R.sup.N) or S; X is H, a protecting group, a phosphate group, a phosphodiester group, an activated phosphate group, an activated phosphite group, a phosphoramidite, a solid support, --P(Z')(Z'')O-nucleoside, --P(Z')(Z'')O-oligonucleotide, a lipid, a PEG, a steroid, a polymer, --P(Z')(Z'')O-L.sup.6-Q'-L.sup.7-OP(Z''')(Z'''')O-oligonucleotide, a nucleotide, or an oligonucleotide; Y is H, a protecting group, a phosphate group, a phosphodiester group, an activated phosphate group, an activated phosphite group, a phosphoramidite, a solid support, --P(Z')(Z'')O-nucleoside, --P(Z')(Z'')O-oligonucleotide, a lipid, a PEG, a steroid, a lipophile, a polymer, --P(Z')(Z'')O-L.sup.6-Q'-L.sup.7-OP(Z''')(Z'''')O-oligonucleotide, a nucleotide, or an oligonucleotide; R is folate, a folate analog a folate mimic or a folate receptor binding ligand; L.sup.6 and L.sup.1 are each independently for each occurrence --(CH.sub.2).sub.n--, --C(R')(R'')(CH.sub.2).sub.n--, --(CH.sub.2).sub.nC(R')(R'')--, --(CH.sub.2CH.sub.2O).sub.mCH.sub.2CH.sub.2--, or --(CH.sub.2CH.sub.2O).sub.mCH.sub.2CH.sub.2NH--; Q' is NH, O, S, CH.sub.2, C(O)O, C(O)NH, --NH--CH(R.sup.a)--C(O)--, --C(O)--CH(R.sup.a)--NH--, CO, ##STR00002## where R.sup.a is H or amino acid side; chain. R' and R'' are each independently H, CH.sub.3, OH, SH, NH.sub.2, NH(Alkyl=Me, Et, Pr, isoPr, Bu, Bn) or N(diAlkyl=Me.sub.2, Et.sub.2, Bn.sub.2); Z', Z'', Z''' and Z'''' are independently O or S; n represent independently for each occurrence 1-20; and m represent independently for each occurrence 0-50.