Corrosion is a major contributor in gas pipeline degradation and failure. Due to significant sources of uncertainties in corrosion progression modelling, nondeterministicapproaches are more promising in recent researches. Several researches were conducted about probabilistic assessment of corrosion and itseffects in practical models. However, in these studies, either internal or external corrosion individually were separately evaluated, without taking intoaccount their correlated effects. In this study, a reliability analysis method is proposed for pressurized bare gas pipeline buried in soil by taking into accountboth corrosion effects from inside and the outside of the pipe. Environment effects are also studied on pipe’s corrosion by considering different soil types. Itwas observed that soil grain size has significant impact in corrosion occurrence. Consequently, sandy clay loam has the highest reliability index while clayand clay loam have the lowest values among these soil types.