Trust in the source of information about physician quality is likely to be an important factor in how consumers use that information in encounters with their doctor or in decisions about choice of provider. In this article, the authors use survey data from a nationally representative sample of 8,140 individuals with chronic illness to examine variation in consumer trust in different sources of physician quality information and how market segmentation factors explain such variation. The authors find that consumers place greater trust in physicians and hospitals relative to institutional sources and personal sources. The level of trust, however, varies considerably across consumers as a function of demographic, socioeconomic, behavioral/lifestyle factors but is not related to measures of context. These results suggest that the sources of public reports comparing physician quality may be a barrier to the use of quality data by consumers in the ways envisioned by supporters of greater quality transparency. © 2011 The Author(s).