The service life of our nation's infrastructure has become a topic of increasing focus in recent years. While above-ground infrastructure deterioration is readily apparent, the infrastructure beneath the surface can be much worse and yet is often largely ignored until it is too late. Since culverts and other buried structures typically are not inspected as frequently as above-ground structures such as bridges, the proper assessment and determination of their service life becomes very important. The design service life of corrugated high density polyethylene (HDPE) drainage pipe has been a subject of considerable research over the past several years. This paper presents a method for determination of long-term service life of corrugated HDPE pipe by utilizing some of the current widely accepted methods employed by the smooth-walled plastic pipe industry while modifying them somewhat to take into account the unique geometry and installation conditions of buried corrugated pipe. The resulting data when tested in accordance to this protocol indicate a service life in excess of 100 years.