Despite various electoral reforms enacted in Mexico between 1988 and 1994, large numbers of Mexicans doubted the honesty of elections and the general integrity of their country's policy making process. Such doubts did not automatically lead, however, to support for the opposition parties that called for greater democratization. Rather, voter preferences were largely dependent on judgments about the opposition's viability and competence. Widespread suspicions about fraud and corruption in Mexico did affect electoral outcomes by making it less likely that potential opposition supporters turned out to vote. Data are drawn from seven national public opinion surveys conducted in Mexico in 1986, 1988, 1991, 1993 (3 polls), and 1995.