Purpose:The concept of sustainable environmental management is relatively new in the understanding of Polish managers. There is a research gap regarding the degree of implementation of this concept in Polish manufacturing companies. The study aims to determine the level of development of sustainable pro-environmental management in a Polish energy production company. Design/Methodology/Approach: The study was conducted in January 2021 on a random sample of 300 people. The response rate was 31%. The respondents were residents of the voivodeship where the energy company is located. The study used secondary data obtained from the company's resources and primary data using the CAWI method. A development index based on the distance from the standard was proposed to assess the degree of sustainable proenvironmental management. Findings: Sustainable environmental management is seen as a new management concept. This trend plays a crucial role in transforming production companies into sustainable economic organizations operating following the principles of sustainable development. The study shows that the pro-ecological activities undertaken by the organization bring benefits for the natural environment, although the environmental performance indicators remain average. In the course of the study, it turned out that communicating the company's activity in the field of environmental protection to the social environment is not carried out professionally. Practical Implications: The way of communicating to society the activities undertaken by the enterprise in the field of environmental protection requires improvement. Upgrading this area of organization management may bring benefits related, among others, to increasing the trust of the community or improving the image of the organization. Originality/value: The article is a pioneering attempt to define the degree of development of sustainable environmental management on the example of a heavy industry company. The study enriches the poor state of the literature on practices in the field of sustainable environmental management.