An apparatus and method for decoding a channel code is disclosed. The method for decoding a channel code includes the steps of receiving a low density parity check (LDPC) encoded signal from a transmitting party, generating a parity check matrix by adjusting the order of rows or columns of the parity check matrix, the parity check matrix including a plurality of groups consisting of a plurality of columns, at least one of the groups including at least one row of which every element is zero (0), and iteratively decoding the received signal for each group by using the generated parity check matrix.