Tanzania enacted the Environmental Management Act (EMA) in 2004 with Environmental Impact Assessment (EIA) as one of its major tools for protecting environment from the impacts of development projects. According to EMA, all new projects have to undertake EIA before they are commissioned. This paper assesses to what extent this has been achieved. The study involved 5 industries (as cases) which have Environmental Certificates, staff of the National Environment Management Council (NEMC) which is responsible to enforce EMA, Municipal Councils, Wards, Registered Environmental Consulting Firms and NGOs. The assessment focused on institutional strength and weaknesses, awareness of industrial staff and resources allocation for implementation of the Environmental Management Plan (EMP) and Environmental Monitoring Plan (MP). The assessment was done through reviewing Environmental Impact Statement (EIS), site observation, interviews and questionnaires. Study findings show that to a greater extent, EMPs and MPs as presented in EIS are not implemented due to existence of institutional weaknesses, low awareness, poor allocation of resources for EMP implementation and weak enforcement. It was thus concluded that; EIA process apart from identifying potential impacts, it does not go all the way to ensure that they are mitigated. The paper proposes recommendations to remedy the situation.