One of the most frequently used questionnaires to assess diverse symptoms in palliative care, is the Edmonton Symptom Assessment Scale. Although this 9 item instrument has proven to be valid in North America, it remains unclear if this instrument is valid and reliable in a different culture with a different language. Therefore, the aim of this study is to test the psychometric properties of the ESAS in a population of Flemish speaking patients who are admitted to a palliative care unit. Demographic variables are gathered from patients, family and nurses. Symptom occurrence and symptom distress are assessed for the 9 symptoms. Different strategies are used to test the psychometrics properties. In a first part of this study, researchers evaluate the relevance and comprehension of the 9 items. Based on literature the researchers compare the different items and evaluate if these items can be grouped as being symptoms relevant to palliative care. During the second part this adapted instrument is presented to a panel of experts in palliative care. These experts mainly assess the relevance of the symptoms based on their experiential knowledge. Based on these comments and an in advance determined cut off score; symptoms will be omitted or retained. Face validity is assessed from patients, nurses and family. In the last part of this study construct validity is tested based on a comparison between groups and starting from evidence based hypotheses. Heise's formula is used and evaluated to test the stability of the different concepts measured with the ESAS. Inter-rater reliability is evaluated by comparing patients', nurses' and families scores. Results of this validation study are presented. Methodological problems as well as the usefulness and possible burden of the assessment are discussed and evaluated from the patients' and researchers' point of view.