A method of encoding/decoding using an LDPC code is disclosed, by which performance is enhanced and by which complexity is reduced. In encoding/decoding using an LDPC code defined by an (n−k)xn parity check matrix H, the present invention includes the step of performing the encoding/decoding input source data using the parity check matrix H including Hp and Hd to meet H=[Hd|Hp] (where Hd has (n−k)×k dimensions, Hp has (n−k)×(n−k) dimensions), wherein if the Hp comprises a plurality of zXz sub-matrices, each of the sub-matrices is an identity matrix or a zero matrix and wherein a column weight of each column of the Hp is at least 2.