BACKGROUND/AIMS: Prognostic factors are an important issue in progressive and life-limiting diseases. This study evaluate 3-month mortality in patients admitted to the palliative care unit (PCU). METHODS: In this study, the patient's demographics, comorbidities, nutritional status, and laboratory values were recorded. The palliative performance scale (PPS), the palliative prognostic index (PPI), and the palliative prognostic (PaP) score were calculated. The rectus femoris (RF) cross-sectional area (CSA), RF muscle thickness, gastrocnemius (GC) medialis muscle thickness, pennation angle and fascicle length of the GC were measured by ultrasound for survival prediction. RESULTS: A total of 88 patients enrolled during the study period, with a mean age of 73.6 ± 13.3 years and a 3-month mortality rate of 59.1%. The findings of a multivariable Cox proportional hazards regression model based on age, gender, C-reactive protein level and Nutrition Risk Screening 2002 scores as covariates revealed the PPI and the PaP score to be significant predictors of 3-month mortality. In addition, in the unadjusted Cox proportional hazard regression analysis, the CSA of the RF muscle was also found to be a significant predictor of 3-month mortality. CONCLUSION: Findings revealed that the combined use of the CSA of the RF, the PPI, and the PaP score are reliable predictors of mortality in patients admitted to the PCU.