A method and apparatus for performing parallel box filtering in region based image processing is provided. The method of performing parallel box filtering in region based image processing includes selecting parallel pixel blocks having a size of M×N to be operated in parallel, selecting pixels included in a mask region having a size of K×L that is a parallel pixel operation region and a first region having a size of (M+K−1)×(N+L−1) that corresponds to overlapping masks of M*N, selecting pixels of a second region commonly included in the mask regions of M*N and storing the results of operation with respect to the pixels of the second region as repeated operation values, and operating block operation values with respect to the parallel pixel blocks using the repeated operation values.