Siege warfare could be defined as the art of capturing forts as well as the techniques involved in defending fortified strongholds. The history of siege warfare from ancient times onwards is a continuous dialectics between developments of offensive weapons for destroying fortifications, which in turn resulted in the innovative modifications of fortress architecture. The East India Company’s (hereafter EIC) Army deployed in India imported the new techniques of scientific siege warfare which emerged in south and west Europe during the early modern era. By making a case study of two sieges conducted by the EIC’s Army during the Great Mutiny, this paper attempts to show that British success was due to the systematic use of firepower and associated technologies in a scientific manner. Cavalry played a marginal role in siege operations. The central components in siege operations were the military engineers with sappers and miners and then the artillery branch. In scientific siege warfare picks and shovels played an equally important role like the mortars and howitzers. The rebels unlike the EIC lacked an engineering branch and a corps of sappers and miners. The British infantry had a technical edge over the rebels in the sphere and miners. The British infantry had a technical edge over the rebels in the sphere of hand held firearms. Both in Delhi and Lucknow, shortages of guns forced the rebels to rely on inefficient traditional guns. In the final analysis, superior hardware and the technical skill in using them properly enabled the EIC to overwhelm the numerically superior rebels.