AimThe aim of the study is to develop a scale to measure nurses' self-efficacy levels regarding safe blood transfusion practice. MethodsThis study, applied in methodological design, was conducted in a public university hospital in Istanbul between March-April 2021. The sample included 372 nurses. A draft form consisting of 75 items was prepared. Content validity, construct validity, distinctiveness, internal consistency reliability, two-half test reliability, test-retest, and item analysis methods were used to determine the psychometric properties of the scale. ResultsThe exploratory factor analysis showed that the scale had a four-factor structure that explained 71.36 % of the total variance. The factor loads of 49 items were found to vary between 0.50 and 0.92. The item-total correlations were found to be between 0.55 and 0.92. The Cronbach's alpha value for the whole scale was 0.96. ConclusionThe results of the analysis show the items constituting Safe Blood and Blood Products Transfusion Self-Efficacy Scale have validity and reliability criteria that can measure the nurses' self-efficacy levels regarding safe blood transfusion practice.