A double stranded RNAi agent capable of inhibiting expression of HAO1 in a cell, wherein said double stranded RNAi agent comprises a sense strand and an antisense strand forming a double-stranded region, wherein said sense strand comprises at least 15 contiguous nucleotides differing by no more than 3 nucleotides from any one of the nucleotide sequences of SEQ ID NO:1 SEQ ID NO:2, SEQ ID NO:5, or SEQ ID NO:6 and said antisense strand comprises at least 15 contiguous nucleotides differing by no more than 3 nucleotides from any one of the nucleotide sequences of SEQ ID NO:3 SEQ ID NO:4, SEQ ID NO:7, or SEQ ID NO:8;
- wherein substantially all of the nucleotides of said sense strand and substantially all of the nucleotides of said antisense strand are modified nucleotides, and
- wherein said sense strand is conjugated to a ligand attached at the 3′-terminus.