In order to obtain the maximum benefit of both construction cost savings and long service life centrifugally cast fiberglass pipe has effectively been used to rehabilitate corroded buried piping. This method is commonly known as "sliplining" where the existing pipe, the host pipe, is relined inplace without having to dig up and replace the pipe. The cost of digging a new trench is saved. In most cases the new liner, centrifugally cast fiberglass pipe, will exhibit more flow with a smaller pipe than was achieved with the original pipe system. This methodology of sliplining is one of several "Trenchless Technologies." This paper suggests when to "Slipline" a corroded pipe with centrifugally cast fiberglass pipe. This information should be helpful in the decision-making process whether to reline with fiberglass pipe or to solve the problem with some other solution. Keywords: Centrifugally cast, sliplining, rehabilitate