Given the popularity of political knowledge questions in political science research, it is critical to understand the measurement of this question type. This study examines the data collection mode effect on political knowledge questions. Specifically, responses to political knowledge questions between face-to-face and Web surveys, and between computer-assisted self-interview (CASI) and Web surveys are compared using the 2012 American National Election Studies. The results suggest that a significant mode effect exists for political knowledge questions. Among the 13 knowledge questions examined, 10 exhibited significant differences between modes. In general, Web surveys elicit more accurate answers than face-to-face and CASI. Easy access to information through the Internet may contribute to the higher level of political knowledge among Web respondents. This finding suggests that political knowledge as measured in Web surveys is not equivalent to that from face-to-face surveys. The result suggests that previously established relationships between political knowledge and political involvement in face-to-face surveys may be different in Web surveys.