ABSTRACTObjective: To determine the correlation between blood gas parameters and central venous pressure (CVP) in patients suffering from septic shock.Methods: Forty adult patients with diagnosis of septic shock who were admitted to the emergency department (ED) of Shohadaye Tajrish Hospital affiliated with Shahid Beheshti University of Medical Sciences, and met inclusion and exclusion criteria were enrolled. For all patients, sampling was done for venous blood gas analysis, serum sodium and chlorine levels. At the time of sampling; blood pressure, pulse rate and CVP were recorded. Correlation between blood gas parameters and hemodynamic indices were.Results: A significant direct correlation between CVP with anion gap (AG) and inversely with base deficit (BD) and bicarbonate. CVP also showed a relative correlation with pH, whereas it was not correlated with BD/AG ratio and serum chlorine level. There was no significant association between CVP and clinical parameters including shock index (SI) and mean arterial pressure (MAP).Conclusion: It seems that some of non invasive blood gas parameters could be served as alternative to invasive measures such as CVP in treatment planning of patients referred to an ED with septic shock.