This descriptive study aimed to investigate the end-of-life decisions made by Thai Muslim patients in the five border provinces, southern Thailand and the factors related to decision making. Three hundred and seventy-five chronically ill Thai Muslim patients were purposively recruited from medical and surgical wards in the general and regional hospitals of the five border provinces in southern Thailand. Data was collected by individual interviews using an interview guide comprising 1) the Demographic Data Form, and 2) the End-of-Life Interview Guide, which included three vignettes followed by closed and open-ended questions regarding their end-of-life decisions and factors related to those decisions. Data was analysed using frequency, percentage and content analysis. The results are as follows: 1) end-of-life decisions toward the three vignettes, it was found that 83.7-88.2% of the subjects decided to forgo any life-sustaining treatment, 6.4-9.3% decided to continue their life-sustaining treatment, 1.9-5.1% of subjects allowed the health team to decide for them and 1.9-3.5% let their family to make a decision for them, 2) for the factors related to end-of-life decisions, it was found that more than 80% of subjects made decisions to forgo, continue, or allow others to make decisions based on Islamic values, other factors that related to their decisions included suffering from chronic illnesses, family burden, outcomes of treatment, belief in the health team and the patient's economic status.