The aim of the study is to demonstrate which pro-environmental initiatives consistent with the idea of sustainable development are undertaken by municipal cultural institutions in Poznan—the largest city in the Greater Poland region in Poland. The diagnostic survey was conducted by means of interviews with directors of municipal cultural institutions or their representatives. A total of 12 (out of 15) municipal cultural institutions from the city of Poznan were surveyed. All were asked to cite specific examples of their activities, visualising their institution’s approach to ecology. The results indicated that the institutions undertake numerous eco-initiatives, which very often fit into the discourse on so-called “deep ecology” and address the sources of the existing environmental crisis. Their activities are also aimed at stimulating a “return to nature” of the city’s inhabitants. In addition to initiatives aimed at the recipients of the offer of individual institutions, many institutions also pay attention to pro-environmental internal activities. In effect, the results could be divided into three general groups, which include internal institutional activities, the implementation of projects on environmental themes, and educational activities in the field of ecology. However, these activities were undertaken individually, as the survey revealed a lack of inter-institutional cooperation on ongoing projects.