The invention relates to cationic siRNAs, characterized in that they are double-stranded RNA fragments, grafted to the ends of which are oligocations, the number of cationic charges grafted being comparable to or greater than that of the anionic charges carried by the internucleoside phosphates of the RNA strands.Linvention se rapporte à des siRNA cationiques, caractérisés en ce quil sagit de fragments dARN double brin, aux extrémités desquels sont greffés des oligocations, le nombre de charges cationiques greffées étant comparable ou supérieur à celui des charges anioniques portées par les phosphates internucléosidiques des brins dARN.