For many research purposes, scholars need reliable and valid survey measures of the extent to which people have been exposed to various kinds of political content in mass media. Nonetheless, good measures of media exposure, and of exposure to political television in particular, have proven elusive. Increasingly fragmented audiences for political television have only made this problem more severe. To address these concerns, we propose a new way of measuring exposure to political television and evaluate its reliability and predictive validity using three waves of nationally representative panel data collected during the 2008 presidential campaign. We find that people can reliably report the specific television programs they watch regularly, and that these measures predict change over time in knowledge of candidate issue positions, a much higher standard of predictive validity than any other measure has met to date.