OBJECTIVE: The purpose of this study was to determine the reliability and the validity of the Persian version of the Moral Distress Scale-Revised among a sample of Iranian nurses.

RESEARCH DESIGN: In this methodological study, 310 nurses were recruited from all hospitals affiliated with the Qazvin University of Medical Sciences from February 2014 to April 2015. Data were collected using a demographic questionnaire and the Moral Distress Scale-Revised. The construct validity of the Moral Distress Scale-Revised was evaluated using principal component analysis and confirmatory factor analysis. Internal consistency reliability was assessed with Cronbach's alpha.

ETHICAL CONSIDERATIONS: This study was approved by the Regional Committee of Medical Research Ethics. The ethical principles of voluntary participation, anonymity, and confidentiality were considered.

FINDINGS: The construct validity of the scale showed four factors with eigenvalues greater than one. The model had a good fit (χ2(162) = 307.561, χ2/df = 1.899, goodness-of-fit index = .904, comparative fit index = .927, incremental fit index = .929, and root mean square error of approximation (90% confidence interval) = .049 (.040-.057)) with all factor loadings greater than .5 and statistically significant. Cronbach's alpha coefficients were .853, .686, .685, and .711for the four factors. Moreover, the model structure was invariant across different income groups.