Background and Study aim: Diuretic resistance in patients with cirrhosis is clinically manifested by the failure to lose weight or ascetic volume despite high dosages of loop diuretics and sodium restriction. Natriuretic peptides(NP) promote natriuresis and diuresis. Atrial natriuretic peptide (ANP) is known to act as a rapid response hormone and Brain natriuretic peptide( BNP) more as a “back up hormone" activated only after prolonged ventricular overload .Pro BNP are more stable and have been suggested to have a longer biological half life than other natriuretic peptides . The aim of this work is to study the effect of vascular volume on serum level of Pro BNP and to find out the difference of serum level of pro BNP in both diuretic resistant and diuretic responder ascites. Patients and Methods: The study was conducted on 89 patients. Patients subdivided into 2 groups :group 1(41 patients) described as diuretic resistance ascites and group 2 (48 patients) as diuretic respondent.In which both groups underwent laboratory and echocardiography study . NT-proBNP were measured by electrochemiluminescence immunoassay “ECLIA " , Doppler echocardiography by using a System FiVe digital ultrasound machine. Results: There was no significant difference between the groups as regards age, serum potassium, liver enzymes, serum bilirubin, total proteins, international normalized ratio or partial thromboplastin time. The following parameters were significantly lower in the diuretic-resistant group: serum albumin and platelet count. However, the diureticresistant patients had higher blood urea nitrogen (BUN), serum creatinine and higher Child score. There were significant differences between both groups regarding serum level of pro BNP, serum and urinary NA, left atrial dimension (LAD) and left ventricular end diastolic dimension (LVEDD) in which all parameter were higher in diuretic respondent versus resistant group. Also significant positive correlation was noted between Pro BNP and serum and Urinary NA, LAD and LVEDD. Conclusion: Pro BNP is higher in diuretic responder than in diuretic resistance group, and although the latter group has a higher level of Pro BNP than the cut off point but it is not enough to induce diuresis. Also we found that decrease intravascular compartment may decrease cardiac chamber expansion with subsequent decrease in the level of natriuretic peptide leading to decrease the response of diuretic.