Upon the evaluation of an electoral reform, two often cited concerns are governability and proportionality. A new electoral system, whatever it is, should respond to the two concerns as best as possible. In Taiwan's changing from SNTV-MMD to MMM, however, reformers invariably accentuated the new system's attributes of enhancing stability of governance while ignoring the possible outcomes of disproportionality. Hence, as expected, the result of election in 2008 produces high governability and low proportionality. This article measures the degree of disproportionality by Loosemore-Hanby index from 1992 to 2008 and explains how disproportionality occurred.