This paper deals with the presence of environmental subjects in the open learning activities offered by the Scientific Museums in the countries of the European Union. By the term "Scientific Museums", we mean all these Science Centres, Natural History Museums, Science and Technology Museums, Discovery Centres and other edifices of this kind (under various names), where people of all ages can discover, explore and learn about the natural world, engaging their curiosity and using their senses. These places are unique resources for informal and lifelong learning, a process central to forging knowledge, skills and positive attitudes about science. 156 Scientific Museums of the 15 European countries (Austria, Belgium, Denmark, Finland, France, Germany, Greece, Holland, Italy, Luxembourg, Portugal, Spain, Sweden, United Kingdom) have been included in this investigation. (Planetariums, Zoos, classical Botanical gardens and Aquariums are not considered, unless they are part of a largest scientific centre of similar kind. Environmental Information Centres of Non Governmental Organizations are not included neither). New technologies in information and communication are often integrated in these Scientific Museums. Multimedia techniques like video, CD, DVD, interactive exhibits, live cameras, picture library, giant display screen etc, are common enough. As far as that concerns the internet, most of them content to use it for information, so as one can easily find on the web site of the Museum how to get there, opening hours, admission fees, daily programme and -at least- dispose an electronic address for communication. The environment is certainly represented in these Centres, usually by its physical and natural component: exhibits about earth or water, collections of plants, fossils, animals, minerals, different types of ecosystems exposed in galleries or in parts of the garden. Curiously enough, the enormous environmental problems on our planet, such as the energy problem, the greenhouse effect, the ozone depletion, the desertification, the deforestation, the pollution problems and many others, are not frequent themes in the activities proposed by Scientific Museums, according to the on line available information . In fact, only 16 from the 156 Scientific Museums (10%) have integrated some aspects of environmental problems in their programmes. Permanent or temporary exhibitions in ecological matters are organized (in the 5% of them), dealing with rare species of animals or plants (threatened by extinction), ecosystem types, biodiversity, saving energy or water, greenhouse effect, or environmental impact on nature in general, while other "in situ" educational applications, like workshops on recycling paper or walks in ecology inspired gardens, are also proposed in some of them (less than 3%). As far as that concerns distance learning activities, 8 Scientific Museums (5%) afford documentation on different environmental subjects by internet, while very few (less than 2%) provide some interesting on line options: you can have a virtual tour in galleries with ecology related exhibits, download activity sheets on ecological matters and even have fun playing on line interactive games, which suggest to the player how to think and act in a sustainable way. Some of these successful paradigms will be presented with further details.