A method and apparatus for intraprediction encoding/decoding is provided. The method includes performing image inpainting based on pixels included in a previously encoded region of a current picture among pixels that are adjacent to a boundary between a current block and the previously encoded region of the current picture in order to predict the current block, and performing prediction encoding on the current block using the prediction result. Thus, a new intraprediction mode in which the current block can be accurately predicted can be provided.