Abstract: Rampant and unregulated bauxite mining activities in Kuantan, Pahang have caused severe deterioration to nearby Pengorak River and Pengorak Beach. Commonly, surface water is treated by using conventional water treatment method that involved coagulation, sand filtration and disinfection processes. However, conventional approach was found to be less effective in treating bauxite contaminated water in the vicinity. In recent years, the use of economical and cost-effective alternative such as Riverbank Filtration (RBF) system has gained widespread acceptance as a reliable method in treating raw water. This study evaluates the treatment efficiency of riverbank soil in Pengorak River in treating bauxite contaminated water. A laboratory scale fixed-bed filtration column test was conducted. Improvements in the water quality were then assessed following Malaysian Department of Environment Water Quality Index (WQI) and classified according to Interim National Water Quality Standards, Malaysia (INWQS). Water Quality Index (WQI) was determined on the basis of nine physico-chemical parameters namely, pH, color, turbidity, Dissolved Oxygen (DO) Total Dissolved Solids (TDS), Total Suspended Solids (TSS), Ammoniacal Nitrogen (AN), Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD). Test results showed that based on WQI and INWQS, the bauxite contaminated water in Sungai Pengorak was initially classified as Class 4 and 5 (i.e., highly polluted), respectively. Interestingly after column filtration test, the water quality improved significantly to Class 1 (clean) and 95.65 with respect to WQI. Due to close proximity to the sea, a much higher TDS value was obtained. The increased in TDS value may be attributed due to migration of salts from the sea during high tide and remained within the riverbank soil. Overall, the treated water complied with the National Drinking Water Quality Standards (NDWQS). Thus, riverbank filtration system may be a viable option for treating bauxite contaminated water.