Abstract: The main gas arising from landfills is methane. The greenhouse effect of methane is 21 times more serious than that of carbon dioxide. On the other hand, this gas has a significant potential for producing energy, so that in cases of application of a suitable technology, a considerable energy from this gas could be extracted and used. One of the mathematical models used for estimation of the amount of methane potential in landfills is LANDGEM software, which was applied in the present research study. This was a descriptive-cross sectional study in which first, the data related to the amount of waste generated, population and landfill characteristics were collected. Then, Sanandaj (study area) population was estimated for different years of the study period with respect to selective growth coefficient. In the last phase, constant value of methane emission and methane production potential in Sanandaj landfill were specified using LANDGEM software. As a result, potential capacity for producing methane in Sanandaj landfill was estimated as 170 m3 t–1 and the amount of output methane during 2018, 2023, 2028 and 2033 is supposed to be 205, 410, 549 and 671 m3 h–1, respectively. Indeed, production speed continues with a lower gradient from 2033 onward. Therefore, the results of current research can be used in designing and measuring the capacity of methane extraction systems from this landfill and in evaluation of Iran’s contribution in global emission of greenhouse gases.