Background: The use of anaesthetics, local or general, is common in hospital setting for surgical interventions. Anaesthetic agents are capable of producing changes on the renal physiology and affecting important biochemical aspects like blood urea and creatinine. It is important to study these effects as they are helpful in determining the safety of such drugs on laboratory animals which can be translated in clinical trials in future research. This experiment was done to determine the effects of ketamine and lidocaine on the level of urea and creatinine in the serum of male Wistar rats. Methodology: A total of 35 adult male Wistar rats were used for this study and they were randomly classified into 5 groups, after one week acclimatization period. These groups included the control group, a lidocaine-treated group without adrenaline, a lidocaine treated group with adrenaline, a ketamine-treated group and a group treated with a combination of ketamine and lidocaine. The anaesthetic agents were administered, at a standard dose, intraperitoneally, and blood samples were obtained after exposure. Biochemical assays to determine serum urea and creatinine were done through the use of standard methods. One way ANOVA analysis with special emphasis on any significant differences among groups was conducted on data. Results and Discussion: It is established in this study that anaesthetic drugs especially the ketamine group has the capacity to increase urea and creatinine levels of rats. This shows that ketamine anaesthetic drug has the capacity to cause kidney disorders. In view of the above, it is recommended that patient undergoing surgeries under ketamine anaesthetics should do so with caution. Pre-operative systemic review should be encouraged. Conclusion: Ketamine and lidocaine greatly affect the level of serum urea and creatinine in male Wistar rats and their combined application had the most significant effects. These findings emphasise the importance of the choice of ana