The importance of soybean production in Austria has increased significantly in the last few years. Therefore the scientific interests have focused on these plants and especial-ly their pathogens. In 2013 Ascochyta sojina, a new pathogen on soybean has ben dis-covered (BEDLAN, 2014). Based on this first record of A. sojina, this master thesis examines the biology of this fungus. The focus areas in this research are growth rate, path of infection, seed trans-mission, susceptibility of varieties and dissemination of A. sojina. The optimum temperature regarding the growth rate of the fungus is 25 C. This re-search shows that A. sojina adjusts growth to temperatures over 30 C and under 5 C, however it remains viable. The fungus intrudes through the stomata into the soybean plants. By analyzing soybeans of pods infected with A. sojina it is proven that the fungus can be transmitted by seed. For this research 85 soybean varieties were tested to find out if the susceptibility to-wards A. sojina differs between the different varieties. For this experiment seed leaves were inoculated with a 4,5x106 conidia suspension and incubated at 25 C for one week. An adjusted evaluation scheme was created regarding the infection rate and resistance towards A. sojina. Most of the soybean varieties have shown a resistance of 60%. There is no vertical resistance since the first leaves are more susceptible than the resilient seed leaves. A. sojina is the second most common phytopathogenic fungus on soybean in the in-vestigated cultivated areas in Austria (HISSEK, 2016). Therefore monitoring of phy-topathogenic fungi on soybeans should continue to provide more information on this fungus, for example the intensity of outbreak and yield reduction.