Background: Respiratory distress is a common and distressing experience that strikes most critically ill patients with cardiopulmonary diseases. Now, most dyspnea assessment tools rely on patient’s self-report. Only one instrument, the Respiratory Distress Observation Scale (RDOS), is valid for assessing respiratory distress when the patient cannot provide a dyspnea self-report. Purpose: The aims of this study were to develop the Chinese version of RDOS through two-way translation and examine its reliability and validity. Methods: The first stepwas the translation and back-translation to establish the Chinese RDOS and examine the semantic equivalence between the back-translation version and the original one. The second step was the psychometric testing of the Chinese RDOS including internal reliability, interrater reliability, concurrent validity, convergent validity, and content and construct validity. Results: The Chinese RDOS was reported with an internal consistency (Cronbach’s ! value) of .73, an interobserver reliability of .97, and a content validity index of .97. In the conscious critically ill patients, significant correlations were found between the Chinese RDOS and Spielberger State Anxiety Inventory scores or Dyspnea Vertical Visual Analog Scale scores (r = .69 and r = .76, respectively; p G .001). In the unconscious critically ill patients, there was a significantly positive correlation between the Chinese RDOS scores and fraction of inspiration O2 (r = .26, p G .05) and a significantly negative correlation between the Chinese RDOS scores and saturation peripheral oxygen (SpO2; r = j.42, p = .001). In addition, it also could effectively identify the dyspnea differences between the first and last days in the intensive care units (p G .001). Conclusions: The Chinese RDOS showed good reliability and validity in conscious critically ill patients. The assessment with the Chinese RDOS could be completed within a short period no matter whether the assessor has nursing background in respiratory care or not. It could help the professionals systematically manage and track the change of respiratory distress in patients.