This study compared physicians' perceptions of the importance, accessibility, and quality of different types of patient information that could potentially be available with Health Information Exchange (HIE) with how they use patient information. The results showed that while the physicians rated the majority of 11 data types as very important, accessible, and of high quality, they regularly used only a few data types before having access to a new HIE system. The three major types of information regularly used by the physicians were diagnoses, current medication lists, and allergy information. This study provides new data about how opinions on the importance of information relate to reported information use. Our findings suggest that having important, accessible, and high quality information does not necessarily lead to routine use, but that much of the early value of HIE may lie in improving access to a few data areas.