A parity unit circuit for use in a parallel, pipelined, low density parity check (LDPC) decoder that implements an iterative, min-sum, message passing LDPC algorithm. The parity unit provides a memory logic block for storing information relating to a current and next iteration of the LDPC computations and includes a “compute 1” logic block for computing a parity message (with sign) for application to related bit nodes and a “compute2” logic block for updating the data stored in the memory logic block for a next iteration of the LDPC decoder.