This paper presents an Improved Offset Min-Sum (IOMS) algorithm for Low-Density Parity-Check (LDPC) decoders, used in 5th generation (5G) mobile communication. The proposed algorithm IOMS applies a multiplication factor to check-node update information messages. The simulation results show that the proposed IOMS algorithm offers a better error correction performance than the existing Min-Sum-based algorithms at the expense of a slight increase in complexity. At the BER of 10–5, the IOMS achieves a decoding gain of 0.1dB with respect to the OMS algorithm.