PROBLEM TO BE SOLVED: To provide a method and an apparatus for selecting interleaver sizes for turbo codes. SOLUTION: During operation, an information block of size K is received. An interleaver size K' is determined, that is related to K", where K" from a set of sizes, with the set of sizes includes K"=a p ×f(p min ≤p≤p max , f min ≤f≤f max ), where (a) is an integer, (f) is a continuous integer between f min and f max and (p) takes integer values between p min and p max (a>1, p max >p min , p min >1). The information block of size K is padded to an input block of size K', as needed, using filler bits, and the original input block and the interleaved input block are encoded, to obtain a codeword block using turbo coders. The codeword block is transmitted through the channel. COPYRIGHT: (C)2008,JPO&INPIT