The method is for decoding an LDPC encoded codeword, the LDPC code being represented by a bipartite graph between check nodes and variable nodes including first variable nodes and second variable nodes connected to the check nodes by a zigzag connectivity. The method includes updating messages exchanged iteratively between variable nodes and check nodes including a first variable processing phase during which all the messages from the first variable nodes to the check nodes are updated and a check nodes processing phase during which all the messages from the check nodes to the first variable nodes are updated. The check nodes processing phase further includes updating all the messages from the second variable nodes to the check nodes, and directly passing an updated message processed by a check node to the next check node through the zigzag connectivity.