In this paper, we present an Integrated Rate control and Entropy Coding (IREC) scheme for JPEG 2000. Based on an efficient heap-based rate allocation algorithm, the characteristics of image content, the subband coefficinet and bitplane weighting models, and the user-specified optimization criteria, the proposed IREC scheme can selectively perform entropy coding only on those parts of image data that are likely to be included in the final bitstream. Since entropy coding is the most time and power consuming part, the IREC scheme can then reduce the overall computation and power consumption of JPEG 2000 encoding procedure. Both theoretical analysis and empirical results validate the advantages of the IREC scheme. For example, when encoding the lenna color image with a targeted compression ratio of 128:1, compared with the separate rate control and entropy coding schemes, about 93% savings in computation and power consumption can be achieved on the entropy coding procedure.