Objective To assess the effects of fluid resuscitation in elderly patients with septic shock by right ventricular end-diastolic volume index (RVEDVI). Method Thirty elderly patients with septic shock with-in 6 hours after onset, admired to intensive care unit of Zhejiang Hospital from January 2007 to October 2008, were randomly divided into control group (n = 15) and experimental group (n = 15). Homodynamic profile of the right ventricular was monitored by using modified Swan-Ganz catheter. Fluid resuscitation was given to the patients of control group monitored by right atria pressure (RAP). The expected efficacy of treatment was the RAP elevated to 8 ～ 12 mmHg. The goal of fluid resuscitation in patients of experimental group was 100～ 200 mL/m~2 RVEDVI corrected by right ventricular ejection fraction (RVEF). RAP, pulmonary artery occlusion pressure (PAOP), RVEF, RVEDVI, acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) and mixed venous oxygen sat-uration (SvO_2) were recorded before and after the treatment for 6 hours in both groups. The concentration of lactate and the lactate clearance rate of patients in both groups after fluid resuscitation were detected. The relationship between lactate clearance rate and ARVEDVI was evaluated by using correlation analysis. Results The percentage of patients reaching goal of resuscitation in experimental group (86.7%) was higher than that in control group (80%), however, there was no significant difference statistically. In goals-achieving group, RVEDVI, △RVEDVI, RVEF(%), RAP and lactate clearance rate(%) of the patients in experimental group were signifi-cantly higher than those in control group [(119.92 ± 15.65) mL/m~2, (38.54 ± 6.63) mL/m~2, (36.08 ± 3.40), (14.46±1.13) mmHg,(58.31 ± 13.36) vs. (99.92±11.71) mL/m~2,(21.00±11.01) mL/m~2,(32.42± 2.47),(13.08±1.08) mmHg,(43.99±16.26); P <0.05]. However, there was no significant difference in PAOP, APACHE Ⅱ and SvO_2 between two groups (P >0.05). The lactate clearance rate in goals-achieving pa-tients with septic shock has a significant correlation with RVEDVI and △RVEDVI (P < 0.01). Conclusions Fluid resuscitation guided by RVEDVI in elderly patients with septic shock is safe and more effective than that guided by RAP.