The question of whether radiology report format influences reading time, comprehension of information, and/or scannig behavior was examined. Three radiology reports were reformatted to three versions: conventional free text, structured text organized by organ system, and hierarchical structured text organized by clinical significance. Five radiologists, 5 radiology residents, 5 internal medicine clinicians and 5 internal medicine residents read the reports. They then answered a series of questions about the report content. Reading time was recorded. Participants also reported reading preferences. Eye-position was also recorded. There were no significant diffrences for reading time as a function of format, but there was for attending versus resident, and radiology versus internal medicine. There was no significant difference for percent correct scores on the questions for report format or for attending versus resident, but there was for radiology versus internal medicine with the radiologists scoring higher. Eye-position results showed that although patterns tended to be indeosynchratic to readers, there were differences in the overall search patterns as a function of report format, with the free text option yielding more regular scanning and the other two formats yielding more jumping from one section to another. Report format does not appear to impact viewing time or percent correct answers, but there are differences in both for specialty and level of experience. There were also differences between the four groups of participants with respect to what they focus on in a radiology report and how they read reports (skim versus read in detail). Eye-position recording also revealed differences in report coverage patterns. The way that radiology reports are read is quite variable as individual preferences differ widely, suggesting that there may not be a single format acceptable to all users.