Spectrum fragmentation, a concept that describes the degree of split for a given portion of spectrum, is a newly emerging issue which can affect productivity and technical efficiency in spectrum use as the telecommunication service paradigm evolves from voice oriented to data oriented services. This paper proposes ten indices, compares them and calculates their values for Korea and Japan. The values of all indices range between zero and one, so one can use them for international comparison of spectrum fragmentation. Out of ten indices, three are Theil indices, comparing the discrepancies between spectrum and subscriber distributions. In addition, this paper discusses policy alternatives to lessen the spectrum fragmentation problem.