Background: Intravascular volume status assessment is one of the most challenging tasks for clinicians in intensive care unit so fluid therapy is considered as cornerstone in improving the outcome of the injured traumatic patients. Assessment of intravascular volume state is achieved by multiple methods; non-invasively (such as arterial blood pressure (ABP), heart rate (HR), and urine output (UOP)) and invasively as using central venous catheter (CVC). Objective: The aim was to assess inferior vena cava (IVC) collapsibility index by using ultrasound and to assess central venous pressure through central venous catheter inserted in internal jugular vein to predict intravascular volume status in injured traumatic patients. Patients and Methods: This cohort prospective study was conducted at Zagazig University Hospitals. It included 36 polytraumatic patients who were admitted in Surgical and Emergent Intensive Care Unit. Male patients represented 55.6% and female patients represented 44.4% of them. Age ranged from 21 to 60 years with mean 35.33 years old, mean BMI was 29.03 kg/m² andthe severity of trauma varies from moderate to severe (AIS grade 2-4). Results: The results showed that the mean of IVC collapsibility index gradually decreased in the second day of assessment to 30-38% and decreased more in the third day to 25-35 %. The mean CVP gradually increased in the second day to 4-9 mmH₂O and it increased more in the third day to 6-12 mmH₂O. This study showed that there was statistically significant inverse correlation between IVC collapsibility index and CVP. Conclusion: IVC collapsibility index has a strong statistically significant inverse correlation with central venous pressure, which is more accurate at low central venous pressure values.