Abstract: This study was done to establish the effects of co-administration of chloroquine with aspirin on kidney function. We monitored renal parameters such as urea, creatinine and electrolytes. The experimental animals were divided into 4 groups. Group 1 received only food and water (control). Group 2-4 received in addition to food and water either single dose with aspirin (8 mg kg 1 body weight day 1), chloroquine phosphate (5 mg kg 1 body weight day 1) or combined therapy of chloroquine and aspirin for 8 days. The chloroquine-treated group showed a significant increase in mean serum urea and creatinine levels (p< 0.05) and significant decrease in mean serum sodium and potassium levels (p< 0.05) when compared with the corresponding values of the control group. This study also revealed that co-administration of chloroquine and aspirin caused a more pronounced decrease in serum sodium and potassium levels. The results of the study suggest that acute administration of chloroquine may affect kidney function, more so when co-administered with aspirin; two drugs sometimes combined in the treatment of malaria in a malaria endemic country such as Nigeria.