For the legislative elections in 2008, Taiwan introduced a new mixed-member majoritarian (MMM) electoral system to replace the single non-transferable vote (SNTV) system that had been in place for half a century. The new MMM system is a sharp departure from the original SNTV system in several institutional designs. Whether the Taiwanese public is ignorant or fully aware of the new electoral system has attracted the attention of many Taiwanese scholars. By taking advantage of survey data conducted between 2007 and 2011, we aim to examine in this research the level of the Taiwanese public s awareness of the new MMM electoral system in the 2008 and 2012 elections, investigating whether most voters are knowledgeable of the new electoral system. We also test whether holding legislative elections concurrently with the presidential election influences the effect of political campaigns on people's learning of electoral knowledge. Furthermore, the extent to which people's knowledge of electoral systems influences their voting participation is also included in our analysis. The findings of this study indicate that the majority of citizens were not fully aware of the institutional components of the new MMM system in the 2008 and 2012 elections. We also confirm that political campaigns play an important role in enriching citizens' electoral knowledge. Citizens' knowledge of the electoral system rises as the election date approaches and declines after the election is held. Moreover, concurrent presidential and legislative elections did negatively impact the relationship between political campaigns and electoral knowledge. The learning effect of electoral knowledge in the 2012 concurrent elections was not as significant as that in the 2008 legislative election. In addition, our findings also reveal a positive relationship between electoral knowledge and voting participation, suggesting that citizens who are more knowledgeable of the electoral system were more likely to vote in the 2012 legislative election.