OBJECTIVE: To investigate the effect of different resuscitation fluids on myocardial mitochondrial function in septic rats. STUDY DESIGN: A total of 180 Sprague-Dawley rats were randomly divided into 15 groups (12 rats in each group), including 3 control and 12 test groups. A septic rat model was prepared in test groups with cecal ligation and puncture. Test groups were randomly divided into sepsis group (without fluid resuscitation), resuscitation group with Ringer's lactate (RL group), resuscitation group with hydroxyethyl starch (HES group), and resuscitation group with albumin (ALB group). Myocardial histopathology was observed, and myocardial mitochondrial function was evaluated. RESULTS: Myocardial mitochondrial membrane potential, Ca2+-Mg2+-ATPase activity, and complex I activity were reduced in septic rats, and the 3 biomarkers of the sepsis group showed a decreasing trend following the extension of time. Complex II activity was unchanged in septic rats; myocardial mitochondrial membrane potential and activity for Ca2+-Mg2+-ATPase and complex I and II were not statistically different between the sepsis and resuscitation groups at the same time-point. CONCLUSION: Myocardial mitochondrial function was damaged in septic rats in a time-dependent manner. Resuscitation with RL, HES, and ALB did not improve myocardial mitochondrial dysfunction in septic rats. © Science Printers and Publishers, Inc.