This synthesis will be of interest to pavement designers and others concerned with the design of asphalt concrete overlays. Information is presented on reasons for overlaying a pavement and on the vaious methods available for design of an asphalt overlay. A pavement overlay may be required because of inadequate ride quality, excessive pavement distress, reduced friction between tire and pavement, high user costs, or inadequate structural capacity for planned use. This report of the Transportation Research Boad discusses the current methods used for designing asphalt concrete overlays with emphasis on deflection-based and analytical procedures.  The report for this topic can be purchased at https://www.trb.org/news/blurb_detail.asp?id=3441