This paper reports a questionnaire-based investigation into the knowledge sources used by nurses in two Turkish university hospitals, and whether these knowledge sources were related to sociodemographic variables. 78.5% of the nurses said that practice should be based on evidence and 75.9% stated that this evidence should come from research. 80.7% stated that evidence-based practice was useful. However, evidence that was not based on research constituted the first three most frequently used sources of knowledge. Sources of evidence-based on research were detected as being in the 4th, 5th, 6th, 8th, and 10th positions regarding the frequency of use. The nurses expressed a belief that nursing practices should be based on evidence, but did not reflect this belief in their behavior. Crown Copyright (C) 2007 Published by Elsevier Ltd. All rights reserved.