Abstract
Background and Objectives
Considering the importance of training of nurses in the field of blood transfusion, we evaluated the level of knowledge of nurses regarding blood transfusion.

Materials and Methods
This was a descriptive cross-sectional study performed on nurses in Shiraz hospitals in 2019-2020. The level of knowledge was determined using a questionnaire before and after the course by pre-test and post-test. The questionnaire consists of two parts. The first part has a questions regarding demographic characteristics . The second part has 28 four-answer questions about blood and blood components, indication, administration and complications. The data was analyzed using SPSS-23 software by paired t tests, chi-square, McNamara , change score t test, Anova ,and  correlation tests .

Results
The mean score of awareness after class was significantly increased (13.47 ± 3.80 from 28 to 20.21 ± 5.45 out of 28) (p < 0.001). The increase in awareness was significant in all blood transfusion items .

Conclusions  
Due to the lack of sufficient knowledge of nurses in the field of blood transfusion the education of nurses is essential to improve blood safety. Therefore, planning training classes in the field of transfusion medicine on a regular and continuous basis and evaluating the impact of education is recommended.