A research paper by Joyce Munie, P.E. Manager, Permit Section, Bureau of Land Illinois Environmental Protection Agency submitted in fulfillment of House Resolution 715 State of Illinois 92nd General Assembly. This report analyzes current liner designs, evaluates the designs effectiveness and relative cost, and evaluates other alternate multiple liner designs including their cost and effectiveness. This report evaluates the current minimum liner design standard in Illinois for municipal solid waste landfills of a single liner system. Analysis of the single liner systems effectiveness for protection of human health and the environment is presented with an evaluation of the doublecomposite liner design for municipal solid waste landfills. This report includes a summary of regulatory requirements from other states for comparison. Finally an evaluation of the relative cost of liner designs is provided.