This study aimed to validate the Arabic version of the two-question Quick Inventory of Depression (QID-2-Ar) in multiple sclerosis (MS) patients living in Syria during the war. METHODS: A total of 100 Syrian MS patients, aged 18-60 years, were recruited at Damascus Hospital and Ibn Al-Nafees Hospital to validate the QID-2-Ar, including analyses of its screening test parameters and its construct validity. RESULTS: The QID-2-Ar screening parameters for depression tested very positively, and its construct validity was also favorable (P<0.01). CONCLUSION: The QID-2-Ar is a good screening test for detecting depression. Using a threshold score of >/=1 rather than 2 resulted in more depressed patients being correctly identified. The Arabic version of the QID-2-Ar also has highly favorable psychometric properties. It is valid for assessing depression, especially the two main depressive symptoms (depressive mood and anhedonia) listed in DSM-V. This is a useful tool for researchers and practitioners, and a threshold score of 2 on the QID-2-Ar is recommended to be more certain that all those with depression are detected without having to use a complete depression questionnaire such as the Beck Depression Inventory (BDI)-II.