ObjectiveExistential distress is a common phenomenon in palliative care cancer patients. Developing a reliable and easy‐to‐use assessment scale for existential distress of palliative care cancer patients is crucial. The aim of this study was to develop a measurement of existential distress for palliative care cancer patients and test its properties.MethodsThe guidelines for developing a scale proposed by DeVellis were followed. Palliative care cancer patients were invited to test the draft scale. Two‐hundred and nineteen valid questionnaires were included for the item analysis and exploratory factor analysis. Three‐hundred and two valid questionnaires were included for confirmatory factor, convergent validity, discriminant validity, and internal consistency reliability analyses. Twenty repeated data were measured for test–retest reliability analysis.ResultsThe Existential Distress Scale for Palliative Care Cancer Patients was developed with nine items and three dimensions, including meaninglessness, alienation, and death anxiety. The confirmatory factor analysis showed that the developed scale had a stable factor structure. The Cronbach's α for the whole scale was 0.81, and that for each dimension was 0.76, 0.67, and 0.70, respectively. The test–retest reliability of the scale was 0.79, and that of each dimension was 0.58–0.64.ConclusionsThe Existential Distress Scale for Palliative Care Cancer Patients is a simple but reliable and valid tool.