Objectives: Nurse's self-concept is significant for professionalism.We aimed to determine the reliability and validity of the Turkish version of a Nurses' Self Concept Questionnaire.Methods: A methodological study was conducted with the participation of a group of nursing students and nurses.For the statistical analysis,structural equation models,convergent validity analyses,discriminate validity analyses,internal consistency analysis,and test-retest reliability analyses were used.Results: Correlation-coefficient for the test-retest reliability of the Turkish version of Nurses' SelfConcept Questionnaire was 0.87.The internal consistency of this questionnaire was calculated with Cronbach's α coefficient and it was found high across the six subscales from 0.83 to 0.91.The goodness of fit indices was determined as acceptable.Conclusions: According to results,this Nurses' Self-Concept Questionnaire is a valid and reliable instrument for assessing nurses' and nursing students' self-concept in Turkey.