Provided are a method and apparatus for encoding and decoding in an intra mode based on a multiple scanning method through which efficiency of the intra mode is improved by using a spatial relationship within a frame more and obtaining estimation information from numerous references. The method includes: dividing an input image into basic encoding units composed of predetermined sized blocks; scanning at least one of the basic encoding units; determining whether references for motion estimation of a current basic encoding unit can be used as references to encode the current basic encoding unit; and encoding the current basic encoding unit according to a result of the determination.