The rehabilitation of concrete freeways has challenged highway authorities for many years. This challenge has been met with the use of various techniques such as full-and partial-depth repairs, diamond grinding, and unbonded overlays. In 1989 the Ontario Ministry of Transportation constructed a project to demonstrate the feasibility of using these techniques on the freeways in its jurisdiction and to monitor the long-term performance of the freeways rehabilitated by these various techniques. The project incorporated the use of full-depth and partial-depth repairs, which was followed by diamond grinding and joint sealant replacement on the northbound lanes. The southbound lanes received a 180-mm-thick undoweled plain-jointed unbonded portland cement concrete overlay, which is the focus of this study. Design of the overlay was undertaken by using PCA design guides, which used the familiar Corps of Engineers square root equation. During the design phase falling-weight deflectometer (FWD) testing was undertaken to assess the pavement condition. Following construction an extensive program was implemented to systematically monitor long-term performance. The program included FWD testing for corner-to-center deflection ratios and joint load transfer efficiencies, along with roughness and skid resistance testing and condition surveys. Roughness and skid resistance measurements have been completed on an annual basis, with FWD testing and condition surveys carried out as needed. The design and construction of the unbonded overlay are highlighted, and the results of the performance monitoring program carried out on this 4-year-old project are detailed.