w. KlingmUller Lehrstuhl fUr Genetik, Universitat Bayreuth, UniversitatsstraBe 30, 8580 Bayreuth, FRG th th On September 6 and 7 1983 the second workshop on "Azospirillum: Genetics, Physiology, Ecology" took place at the University of Bayreuth, west Germany, organized by the genetics department. There were about 50 participants, who came from German research institutions, from other European countries, from Israel, Egypt and North and South America. The first such workshop had taken place two years ago in Bayreuth too, hence the organizers could draw on the experiences then obtained. Azospirilla have, during the past ten years, found an ever increasing scientific interest, because first, these soil bacte­ ria carry the genetic information for binding molecular nitrogen from the air, and second, they live in close vicinity to the roots of several grain crops and forage grasses. By exploitation of these two properties, it is hoped to develop inoculation pro­ cedures that result in yield increases in agriculture, in par­ ticular in soils poor in nitrogen. The reports on the first afternoon focussed, as a result of the Bayreuth research interest, on the genetic basis and the regulation of nitrogen fixation in Azospirillum. Here, mainly by application of most modern gene technological approaches, considerable progress in the understanding of the situation has been made, and was documented in the corresponding reports.