Transportation of Oil and Gas from the production site to the terminal or refinery requires the use of long pipelines which procure to develop slug flow regime. This slug may cause cyclic stresses leading to fatigue and results in damaging the pipelines. This paper aims to utilize that design guide and calculate the total fatigue life for the pipeline due to internal slug flow by performing evaluation of the stress range and fatigue life span of the pipeBeam 3element with moving loads in ANSYS commercial software have been used to simulate the slug flow across the pipeline and assess the dynamic response. The total fatigue life for different selected slug parametrs was calculated. The model was validated by comparing with analytical solution in a previous published research and reasonable agreement was revealed. The results show that increasing the slug to pipe weight ratio resulting in higher dynamic stresses and reduction in the fatigue life of the pipe. This model can be utilized for the offshore pipeline if the external environmental effects are considered. © (2014) Trans Tech Publications, Switzerland.