The purpose of this research is to explore the practice of Environment Management Accounting (EMA) in PT Semen Indonesia (PT. SI) as an effort to assess Eco-efficiency. The research was conducted by using qualitative method to ensure in depth understanding of the topic researched. The data collected consists of: (1) interview transcript, (2) supporting documents, and (3) direct observation. This research revealed that PT SI incentives in maintaining Eco-efficiency are mainly due to stakeholders’ demand, especially government, foreign shareholders, and surrounding community. PT SI’s focus of data monitoring is still mainly on physical information from non-accounting department (PEMA), while the company record monetary information (MEMA) in separated recording. The cost allocation for environmental costs are still buried inside overhead costs, therefore, it lowers the accuracy and extensiveness of financial information provided through MEMA. Since qualitative research is used, then the research limitation relates to the methodological issues which is the research results cannot be generalized but it might be transferred to other company. Perhaps in the future the need for more advanced environmental costs tracing will emerge and thus PT. SI will begin to optimize to use both PEMA and MEMA to help them to identify their environmental costs more accurately. This paper contributes to the empirical research on environmental and performance management by integrating these two issues, and also illustrates that forces are dynamic rather than static.