Background: Cardiorenalsyndrome has been defined as the simultaneous dysfunction of both the heart and the kidney. In this setting, worsening renal function (WRF) is a common finding. Objective: The aim of work was to determine whether venous congestion, rather than impairment of cardiac output, is associated with the development of WRF in patients with decompensated heart failure (DHF). Patients and Methods: This observational prospective study included a total of 30 adult Egyptians patients with DHF, attending at Ain Shams University Hospitals. Inclusion criteria: 1. Left ventricular ejection fraction < 50%. 2. CVP > 10 mmHg. 3. Right ventricular systolic pressure > 40 mmHg. ECHO was done for all subjects. Follow up of s. creatinine, GFR with MDRD equation, CVP, MABP and body weight were done daily for a week. Results: At follow up, 11 (36.7%) subjects developed WRF and 19 (63.3%) did not. that there was an incremental risk in WRF with increasing baseline CVP, as it appears to be a near linear relationship, because if the baseline CVP reached >19 or > 24 mmHg, we observed a sharp increase in the incidence of WRF approaching 51% and 71%, respectively. Furthermore, the mean baseline CVP was higher in subjects who developed WRF (26.2±3.3 mmHg) versus those who did not (18.1±1.9 mmHg) ( p<0.001).We have also noticed that baseline EF was significantly lower in subjects who developed WRF .We also noticed that Subjects who developed WRF had lower eGFR at baseline. Conclusions: It could be concluded that in the setting of DHF, venous congestion (high CVP) may be the most important driving factor of WRF rather than low COP.