Abstract: As a result of urbanization and industrialization, the world started facing some environmental complications such as urban heat island which can raises air temperature to about 2-5% in a city or more, noise and air pollution, storm water run-off, ultra violet radiation etc. But the introduction of green roof in our modern buildings after a series of researches in late 20th century especially in Germany and other European countries tend to minimize these environmental complications to a reasonable level. Therefore this paper is going to discuss about green roofing in buildings with reference to its history, types, application, and its benefits on the environment. Furthermore, some case studies of both intensive and extensive green roof were selected randomly from some buildings and which were compared, discussed, conclusion and recommendations were drawn from the case studies.