Conservation is very important for Islamic enterprises in their effort to protect the environment. This research examines the effect of conservation on the environmental performance of Indonesian Islamic enterprises from the perspective of legitimacy theory. The relationship between conservation and environmental performance examined and tested using Partial Least Square-Structural Equation Model (PLS-SEM). The results of the study showed positive influence of conservation on environmental performance at Islamic enterprises to guarantee the quality of human life. It was recommended Institute of Indonesia Chartered Accountants (IAI) publish the Environmental Accounting Standards.