A data processing apparatus, a data processing method, an encoding apparatus, and an encoding method which can be applied, for example, to a transmission system for transmitting an LDPC code and so forth, and which can improve tolerance to errors. Of an LDPC code which is prescribed in the DVB-S.2 and has a code length of 64,800 and an encoding rate of 2/3, mb code bits are replaced, and the code bits after the replacement become symbol bits of b symbols. When m is 8 and b is 2, where the i+1th bit from the most significant bit of 8×2 code bits and 8×2 symbol bits of two successive symbols are represented by bi and yi, respectively, replacement of allocating b0 to y15, b1 to y7, b2 to y1, b3 to y5, b4 to y6, b5 to y13, b6 to y11, b7 to y9, b8 to y8, b9 to y14, b10 to y12, b11 to y3, b12 to y0, b13 to y10, b14 to y4 and b15 to y2.