In Mexico a reformed curriculum is being implemented at the national primary level focused on the competence model and incorporating EE as a key element. This article reports our analyses of what theories, policies and/or EE related-contents were included in the documents that integrated this curriculum: general study plan, study programs of Grades and official students' textbooks. Results indicate that in those official documents was incorporated a competence related to EE called "competences for the coexistence", implying harmonic relationships with others and the nature. Additionally, EE for sustainability was included as a transversal topic expecting that contributes to reach the graduate profile of basic education that indicates that students should promote and assume the care of health and the environment. Nevertheless, it is not clear how it is expected that teachers implement EE in practice, lacking clarity of the environmental theory that support this curriculum.