This project presents a computational study to examine lateral impact behavior of pressurized pipelines and to determine influence of internal pressure on the pipelines on their impact behaviors. A total of more than 300 numerical simulations were carried out on mild steel pipe models with different internal pressure levels and were struck at the mid-span and at the one quarter span positions. These numerical simulations of the impact tests were performed using 3D dynamic nonlinear finite element analysis (FEA) through LS-DYNA, where both geometrical and material nonlinearities were considered. The computational results for the first time systematically revealed the effects of internal pressure, impact position, and outside diameter on the lateral impact behavior of the pipeline models. The outcomes of this project will have potential benefits on research of safety and reliability of civil pipelines and development of advanced pipeline materials.