Provided are a method and apparatus for encoding and decoding based on intra prediction. In the method, information regarding a direction of intra prediction of a current block is encoded into one of a plurality of values, depending on whether the directions of intra prediction of neighboring blocks that have been encoded before encoding the current block are identical to one another and whether the direction of intra prediction of the current block is identical to those of the neighboring blocks. Accordingly, it is possible to increase the compression rate of intra prediction encoding with a higher probability.