Reed-Solomon (RS) decoder is ideal for correcting errors that occur in clusters. Clustered bit errors are usual when there is frequency selective fading or multipath fading. RS coding is a block coding technique. These codes are generally designated as (N,K,T) block codes. ‘K’ is the number of information symbols per block, ‘N’ is the number of symbols per block and T is the number of correctable errors. This decoder is capable of decoding shortened and punctured coded. This can be controlled in real time allowing block by block code rate changes. The RS Decoder is optimized for WiMAX. This core is written in VHDL, capable of being used on any FPGA/ASIC architecture.