For the past five years, I have been conducting this session to discuss the systems of life-support in closed bio-ecosystems. Living organisms on the earth have evolved considerably since the planets origin. These organisms have adapted several functions by which they coexist, and have thus become mutually dependent upon each other. Knowledge of these functions and the ways in which they interact with the environment is essential for designing a closed-ecosystem, with a limited number of living species in harsh environments, such as extraterrestrial, deep sea or desert. The important elements related to the closed bio-ecosystem have to be discussed among the researchers who have individual specialized fields. Here, we will discuss the details of several species of organisms selected for closed bio-ecosystems. At this time, speakers of various ages will present their researches related to organisms in closed bio-ecosystems.