Summary. This paper is concerned with the general methodology adopted in the empirical investigation of regional economies by the input-output (I-O) approach. In this paper, special consideration is given to the mixed or the so-called hybrid approach of compiling the bi-region inter-regional I-O table for the Philippine economy as a pioneering research project, made recently possible through the logistical support provided by the Japan Society for the Promotion of Science (JSPS)-Manila Project The first sections of this paper present an overview of the status of I-O accounting in the Philippines and a review of literature on regional I-O compilation techniques. Section IV describes the conceptual and accounting framework of the bi-regional I-O model used, followed by a fairly detailed discussion of the general procedure of compilation under the hybrid methodology. The non-survey technique of generating regional I-O coefficients is also being described and illustrated so that clear distinction between the two approaches could be made. The next section deals with a summary discussion and illustration of the significant findings of the empirical study. It highlights an analysis of the relative differentials of calculated total (direct + indirect)output multipliers. Finally, the paper concludes with some recommendatory measures geared towards improving I-O research methodologies, given the existing limitations of the hybrid approach.