A method and apparatus for coding an image capable of performing a prediction coding process by using a correlation degree between neighboring pixels of a current block and neighboring pixels of a reference block, and an image decoding method and apparatus. In the method, reference block candidates having neighboring pixels similar to the neighboring pixels of the current block are selected, matching errors between selected reference block candidates and the current block are calculated, and a reference block candidate having the least matching error is determined to be a predicted block of the current block.