Background Patient dignity is sometimes neglected in intensive care unit (ICU) settings, which may potentially cause psychological harm to critically ill patients. However, no instrument has been specifically developed to evaluate the behaviors of dignified care among critical care nurses. Aim This study aimed to develop and evaluate ICU Dignified Care Questionnaire (IDCQ) for measurement of self-assessed dignity-conserving behaviors of critical care nurses during care. Methods The instrument was developed in 3 phases. Phase 1: item generation; phase 2: a two-round (...) Delphi survey and a readability pilot study; phase 3: cross-sectional survey with model estimation. The questionnaire was evaluated by item analysis, exploratory and confirmatory factor analysis, assessment of internal consistency reliability, and test-retest reliability. The investigation was conducted using a convenience sample of 392 critical care nurses from 6 cities in Zhejiang Province, China, of which 30 participated in the test-retest reliability survey 2 weeks later. Ethical considerations The study was approved by ethics committee. All participants provided written informed consent before the survey. The questionnaire survey was anonymous. Results The results showed acceptable reliability and validity of the IDCQ. The 17-item final version questionnaire was divided into 2 dimensions: absolute dignity and relative dignity. These two factors accounted for 62.804% of the total variance, and model fitting results were acceptable. The Cronbach’s alpha coefficient of the questionnaire was 0.94, and the test-retest intraclass correlation coefficient (ICC) was 0.88 after 2 weeks. Conclusions This study developed a brief and reliable instrument (IDCQ) to assess dignified care in ICU nursing. It can help critical care nurses identify their behaviors in maintaining patient dignity and discover their deficiencies. It may also serve as a clinical nursing management tool to help reduce patient disrespect experience in ICU. (shrink)