A hazardous waste landfill can be regarded a complex system, with many components that contribute to the overall environmental performance of the facility. These include access control, waste containment, drainage systems, operations, gas management systems, and so forth. Of these components, the landfill liner is the first line of defense against long-term environmental contamination. While the requirements for and behavior of compacted clay liners (CCLs) are generally known, the geosynthetic components of hazardous landfill liners also require understanding and informed design. This paper considers issues currently considered in hazardous waste landfill liner design in South Africa, including sub-soil drainage requirements, desiccation, chemical compatibility issues, slope stability issues, and leachate collection requirements. It is noted that this paper cannot be considered to be exhaustive, given its brevity.