This descriptive study was planned to identify blood transfusion practice and knowledge of 100 nurses from three hospitals in Ankara, Turkey. Data collected through observation and interviews were evaluated using percentages, χ2, and correlation methods. Nurses' knowledge and practice related to blood transfusions were measured against a total score of 100. None of the participating nurses achieved a score of 100, and only a few had scores higher than 50. Although a positive correlation existed between the nurses' knowledge and practice scores, the correlation coefficient was insignificant. There was a statistically significant relation between the experience and knowledge scores, but not between the experience and practice scores. The results of the study showed insufficient knowledge about blood transfusion, which was reflected in undesirable practice.