A method for indicating a combination between a codeword and a layer in a MIMO communication system, a layer mapping method, and a data transmission method using the same are disclosed. A minimum number of codeword-layer mapping combinations from among all available combinations based on the numbers of all codewords and all layers are pre-defined in consideration of a ratio of a codeword to a layer, a reception performance of a receiver, and reduction of combinations, so that a data transmission method using the predefined combinations is implemented. If a specific one codeword is mapped to at least two layers, a diversity gain can be acquired.