Full text can be accesed at http://www.ajol.info/index.php/ajest/article/view/71916Tanzania has had an interesting history of Environmental Impact Assessments (EA). Few assessments were conducted prior to 2004 leading to a process of voluntary compliance without explicit laws to enforce the process. Even without a comprehensive legal and institutional framework, those EIAs generated useful policy decisions. Fundamental changes came after 2004 when Tanzania adopted the first ever-comprehensive legal and institutional framework – that is, the Environmental Management Act Cap 191. This Act promotes Environmental Assessment, gives it the legal support and defines the institutional set up for the management of the environment. However, Tanzania still grapples with EIA ineffectiveness in guiding development decisions and environmental management arising from various projects. Numerous studies on the effectiveness of EIA have explored governance issues such as stakeholder participation, legislating EIA process, capacity building and institutional arrangement. Few studies have looked at governance issues such as accountability of responsible institutions in enforcing environmental assessments and procedures. This article discusses accountability challenges in enforcing laws for EIA by exploring the experiences of selected development decisions in the post 2004 in Tanzania. The article argues that, inadequate or lack of accountability in enforcing the Environmental Management Act is a governance failure, that renders the EIA process ineffective. The article calls for a re-assessment of the theoretical arguments used to understand effectiveness to include sociological and psychological factors, that influences accountability actions by environmental agencies and planners.