The present invention relates to double-stranded RNA compounds with at least one blunt end comprising at least one 3'-end of Formula (I): wherein X is O or S R.sub.1 and R.sub.2 are independently OH, NH.sub.2, SH, alkyl, aryl, alkyl-aryl, aryl-alkyl, where alkyl, aryl, alkyl-aryl, aryl-alkyl can be substituted by additional heteroatoms and functional groups, preferably a heteroatom selected from the group of N, O, or S or a functional group selected from the group OH, NH.sub.2, SH, carboxylic acid or ester; or R.sub.1 and R.sub.2 may be of formula Y-Z where Y is O, N, S and Z is H, alkyl, aryl, alkyl-aryl, aryl-alkyl, where alkyl, aryl, alkyl-aryl, aryl-alkyl can be substituted by additional heteroatoms, preferably a heteroatom selected from the group of N, O, or S; and wherein said double-stranded RNA mediates RNA interference. Preferred 3'end modifications are: phosphate, phosphorothioate, abasic ribonucleoside, hydroxyphopyl phosphodiester.