Background Considerable information has been reported on the adverse effect of benzodiazepines on the brain, with limited information of their effects on biochemical parameters. Aim This study aimed to investigate the effect of diazepam and bromazepam on selected biochemical parameters of albino Wistar rats. Materials and methods Diazepam and bromazepam at concentrations of 0.0046 mg/100 g body weight, 0.0036 mg/100 g body weight, 0.0026 mg/100 g body weight, and 0.0016 mg/100 g body weight were administered, respectively, to rats on a daily basis. At the end of each week, total serum protein, glucose, urea, and creatinine levels were evaluated. Histopathological examination of the liver was also performed for signs of possible damage. Results Reductions in serum glucose and creatinine levels were observed in the first, second, third, and fourth weeks in rats administered diazepam and bromazepam at various doses. Both drugs showed similar effects and the reductions were only significant (P Conclusion Although hematological parameters such as glucose and urea were not affected significantly, the observed hepatotoxicity could be indicative of possible induction of hepatic damage with consequent metabolic aberrations.