Sanitary landfill is a waste disposal facility that has control over the potential impact of solid waste by using impermeable liners to prevent contamination of the environment. Several studies improved the impermeability of compacted clay liners by adding bentonite. However, bentonite is an expansive soil susceptible to volume change that would cause the deterioration of the sanitary landfill liner. Hence, the study aimed to investigate the effectiveness of compacted clay mixed with polyurethane as a sanitary landfill liner since polyurethane is a polymer known for its stability and impermeability. Through experimentation using a rigid wall permeameter, it was inferred that the hydraulic conductivity of the compacted polyurethane-clay is acceptable as a sanitary landfill liner. On the other hand, the compacted clay with the same initial void ratio as the compacted polyurethane-clay is not an acceptable landfill liner. Thus, the changes in the soil structure induced by adding polyurethane to the clay has a significant effect on the permeability characteristics.