BACKGROUND: For perioperative nurses to learn effectively, it is critical that they use reliable tools to articulate their own learning needs. However, no tool exists to assess and clarify their learning needs. OBJECTIVE: To develop a reliable and valid learning needs assessment tool for perioperative nurses. DESIGN: A cross-sectional, methodological study was used to develop the tool and examine its reliability and validity. SETTING: Hospitals with operating departments throughout Japan. PARTICIPANTS: A total of 348 perioperative nurses working in hospitals across Japan participated in the study. METHOD: This study was conducted in two phases. 1) Questions were created and scaled based on the results of qualitative inductive research. Content aspects were examined through an instrument review meeting and two pilot studies. 2) The reliability and validity of the assessment tools were examined using primary and secondary surveys. The reliability was examined using Cronbach's alpha coefficients and retest method. Validity was examined using principal component analysis, structural equation modeling, and known-group techniques. RESULT: Cronbach's alpha value was 0.951, indicating internal consistency of the assessment tool. The reliability coefficient of the retest method was 0.56 (p <
.1), indicating stability. The principal component analysis showed an absolute value of the loading of all question items on the first principal component as 0.3 or more and a contribution rate of 48.7 %. The structural equation modeling found that p <
.001, and the goodness-of-fit index = 0.989, adjusted goodness-of-fit-index = 0.983, root mean square error of approximation = 0.099, and comparative fit index = 0.991. This indicated the unidimensionality of the assessment tool and evidence of the structural aspects of validity. The known-group technique supported two hypotheses and provided evidence of the external aspects of validity. CONCLUSIONS: The developed assessment tool has high reliability and validity. Identifying learning needs using this assessment tool will help perioperative nurses fulfill their learning needs.