A transmitter is provided. The transmitter includes: a segmenter configured to segment information bits into a plurality of blocks based on one of a plurality of preset reference values; an outer encoder configured to encode each of the plurality of blocks to generate first parity bits; and a Low Density Parity Check (LDPC) encoder configured to encode each of the plurality of blocks and the first parity bits to generate an LDPC codeword including second parity bits, wherein the one of the preset reference values is determined depending on at least one of a code rate used to encode each of the plurality of blocks and the first parity bits and whether to perform repetition of at least a part of the LDPC codeword in the LDPC codeword.