This paper discusses latest development in industry on Magnetic Tomographic Inspection (MTI) based Fitness for Service (FFS) assessment initiated by PETRONAS on couple of its pipeline in collaboration with Offshore Oilfield Services and IGSAT. The development uses MTM-G inspection result as one of the MTI’s tools to determine remaining life of a pipeline based on predicted degradation profile of a pipeline from magnetic stress growth from metal loss, corrosion defects detected by the MTM-G. This inspection is able to classify mechanical stresses by different component i.e. into hoop, longitudinal, and other any various complex combinations (bending, twisted, shear stresses, and etc.), thus it is relatively to predict the degradation profile of a corrosion defect something similar to a corrosion rate properties. Meanwhile, this scope of this FFS covers MTI technology that come with a failure or safe operating pressure, Pf and Psafe, respectively. It covers for metal loss type of defect only, covering current as well future integrity determination in a form of remaining life. In predicting the future pipeline integrity, the concept of Psafe degradation over time is applied assuming that the corrosion degrades the integrity of a pipeline causing its failure or safe operating pressure reduces over time. There are two methods in estimating the projected pipeline integrity, either with or without previous inspection data. Previous inspection data in this manner is not necessarily restricted to MTI data, but it can be others inspection method as long as there is Psafe being identified or calculated from the inspection outcome. With the development of the MTI based Fitness for Services, un-piggable pipelines remaining life that were mostly inspected by MTI would be able to be identified, thus repair plan can be planned accordingly, or even risk-based inspection can be applied to determine reinspection plan prior to repair commencement.