Remote sensing/satellite observation of land and oceans is a field of research that was developed during the second half of the 20 th century, and its importance is widely recognised because of the amount of information it can provide to the scientific community and the general public. The outcomes of remote sensing/satellite observation can be used to address and study significant aspects of environmental concern, such as habitat destruction, environmental degradation, forest fires, oil spills, and climate change. There is continuous improvement of the methods and means of remote sensing observations in order to achieve more accurate and useful information. The main advantage is the possibility of observing large areas, and the main disadvantage is that it can observe only the water and land surface. The present paper is an effort to review the technologies used in remote sensing and the general applications in a comprehensive manner addressed to scientists who do not specialize in this area of research. Furthermore, this paper reviews case studies/applications in the Mediterranean Sea, an area affected by various polluting activities (industrial cities, agriculture, shipping, etc.) that should be continuously monitored so that the coastal countries are able to successfully manage this sensitive environment.