The size and ageing of the Chilean scientific community was studied using as data the individuals actively engaged in research projects funded by the National Fund for Scientific and Technological Development (FONDECYT). Between 1982 and 1991, 4966 individuals participated at least once, either as responsible for the research or as qualified associate in one term of the funding period. From this population, 2765 persons can be considered further committed with scientific research. As for sex, about 30% of the researchers are women. Taking into account all the disciplines, and in addition to the fact that the size of the Chilean scientific community seems to be subcritical, the study reveals that the workforce has been ageing dangerously through the years. The number of young scientists becoming part of the scientific workforce is decreasing. Research in mathematics, physics and chemistry, although qualitatively competitive, relies only on an extremely small group of excellent scientists, situation which is seriously affecting the scientific capacity that the country needs. Biology, although with a higher number of individuals, exhibits a pattern of ageing which will also affects the possibilities to strengthen the scientific demands. The global context in which science develops, leads to a brain drain that Third World countries will have to overcome, implementing public policies to offer the support that young people require to nurture the scientific strength. Indigenous Ph. D. programs demand urgent attention of policy decision makers as well as from research universities which need to offer opportunities to substitute, when existing, their incompetent faculty.