Description: Rhabdomyolysisis associated with extensive muscle injury accompanied by the secondary renal failure due to myoglobin deposition in the kidney. It has been shown that administration of acetaminophen in a rat model of rhabdomyolysis was effective in improving renal function and decreased renal damage. In this study, the effects of flunixin meglumine administration in a rat model of rhabdomyolysis were investigated. Four groups of rats (8 rats in each group) were employed in this study. Group 1 served as control, the glycerol (Gly) group was given 50 percentage glycerol (7 mL/kg, i.m.), saline-NSAID group received saline injection in place of glycerol and flunixin meglumine daily (2 mg/kg, i.p.), and Gly-NSAID group was given glycerol and flunixin meglumine. Ninety-six hours after glycerol injection, blood samples (2-3 mL) were collected by heart puncture. Serum concentrations of creatinine, blood urea nitrogen (BUN) creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) were measured in serum samples. Gly and Gly-NSAID groups had higher serum concentrations of creatinine, BUN, ALT, AST and CK than the control and saline-NSAID groups (P<0.05). The Gly-NSAID group had higher serum creatinine and BUN levels than the Gly group (P=0.022 and P=0.04, respectively). It seemed that flunixin meglumine administration decreased the muscle injury, however, it increased the renal damage and hence administration of flunixin meglumine in rhabdomyolysis cases needs more consideration