Nigeria is still considered one of the countries with the highest prevalence of protein energy malnutrition. Cassava is a staple food in many parts of Nigeria and it is processed into different forms in different parts of the country, among the commonest of which is gari, which is often consumed by many people without being supplemented explaining partly the prevalent malnutrition. In this study, we investigated the possible effects of gari-based kwashiorkorigenic diet on the renal function which is central to maintenance of homeostasis. We used 24 weanly albino rats divided into two groups. One group was fed with Low Protein Diet (LPD) while the other was fed with normal Commercially Produced Diet (CPD), for 8 weeks. The results showed significant negative effects on both the growth, as shown by the body weight and the kidney size and function in the rats fed with the gari-based low protein diet. The percentage weight change (% + SD) and relative kidney weight for CPD and LPD groups were +340.95+2.63 and 0.51+0.02; -2.03+0.49 and 1.03+0.07, respectively. The Blood Urea Nitrogen (BUN) (mg dL-1), serum creatinine (mg dL-1) and the BUN/creatinine ratio were found to be 19.1+0.84, 0.81+ 0.11 and 24.47+1.18 in the CPD group but 93.42+6.68, 1.92+0.04 and 24.47+1.18 in the LPD group. Similarly, blood pH tended towards acidity in the test group, 6.80+0.04 compared with the control, 7.40+0.03. Therefore, we concluded that during chronic protein-energy malnutrition due to consumption of poorly supplemented gari-based diet, certain renal functions are compromised.