Bangladesh is one of the poorest countries in the world, on a small land with a vast population. Natural gas is the only significant commercial energy resource of the country, and, therefore, future development of the country largely depends on the judicial management of the valuable resource. Estimation of gas-in-place (GIP) and gas reserves are very crucial for the national policy related to energy planning, use, and sale. A wide variety of estimations is reported in different sources over time, which has created a general perception of uncertainly, both locally and internationally. This article highlights the engineering sources of this uncertainty by presenting an interesting comparative study of GIP and gas reserves using three different methods (volumetric, material balance, and flowing material balance [FMB]) for a number of gas fields in Bangladesh. The comparison shows that the latest estimation is significantly higher than those initially estimated. This is because of the inclusion of some new information from development wells, as they have been available. Also, the article has highlighted the benefit of using FMB technique compared to using the conventional material balance technique.