Taiwan’s new MMM legislative electoral system first implemented in 2008 was a sharp departure from the half-century long SNTV system. This paper examines effects of knowledge of the new electoral system on citizens’ decisions to vote or not to vote. Existing literature on voting either assumes that voters are fully aware of the electoral system and thus ignores the effect of knowledge or at best assumes it is an exogenous factor. This study distinguishes itself from other related works in three respects.