Bangladesh. Biogas activities in Bangladesh have been expanding to meet the needs of alternative energy sources and reduce of the country dependence on biomass energy. Biogas is viewed an innovative and most promising option toward a partial mitigation of the existing energy problems in Bangladesh. This study examined the cost-capacity relationships of biogas plant use while considering the financial and economic feasibility with several decision making tools. Data were collected from 150 small scale biogas plants from four districts of Bangladesh. Often three sizes of biogas plants- small (2.4 m3), medium (3.2 m3) and large (4.8 m3) were found in the sample areas. Financial and economic analyses were done based on the decision making tools of Net Present Value (NPV), Internal Rate of Return (IRR), Payback Period (PBP), and Net Benefit Increase (NBI). Four scenarios (with subsidy, without subsidy, health benefit, and income generate from time savings) and one scenario (carbon trading) were accounted under financial and economic evaluations, respectively and stated that biogas plants can be installed as profitable business in the potential areas of Bangladesh. The results highlighted that the investment cost would have a burden of biogas users while subsidy and credit were played a vital role to adopt the decision on biogas plant adoption. Considering five sensitive cases the investment cost also acutely inspired to implement the biogas project across the country. Finally, it may conclude that Bangladesh having a great potentiality to adopt more biogas plants, especially in the livestock prone areas for mitigating the existing environmental degradation, biomass difficulties and generating the income with good health.