This thesis presents a computational study to examine lateral impact behavior of pressurized pipelines and to determine influence of internal pressure on the impact behaviors of pipelines. 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. 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. It inspects effects of important parameters such as the outside diameter and internal pressure. Quartic polynomial functions are applied to formulate the maximum crushing force (F), permanent displacement (W), and absorbed energy (E) of the pressurized pipelines during the impact problem. Response surfaces are plotted based on the generated quartic polynomial functions and the quality (accuracy) of those functions are verified through several techniques.