This study employed an online survey to examine the influences of media reliance compared to motivations in determining credibility of political blog. The survey data was collected during one month at the end of 2009 when Three-in-One election was taken place in Taiwan. The study found that perceived credibility of people who had experiences of visiting political blog was significantly higher than those who had not. By the sample of those who had experiences of visiting political blog, results revealed that people who relied on blog perceived credibility higher than those who relied on other media. Motivations were proved to be a stronger predictor than media reliance after controlling for demographics. Furthermore, information-seeking motive had the strongest power in predicting creditability after demographics and media reliance were controlled.