The objective of this work was to find out the cause of the low level of germination in laboratory, and to suggest measures that could avoid the discard of a great number of soybean seed lots produced during the 1979/80 growing season in the State of Paraná. Several tests were carried out with seed from different places and seed producers of that State. The tests were the following: standard germination test at constant temperatures of 25 and 30oC; seed health test; tetrazolium test; and emergence in greenhouse. These fests were made with untreated seed (check) and treated seed (fungicide and sodium hypochiorite). The main factor responsible for the low germination "in vitro" was the fungus Phomopsis sp., which occured internally in the seed coat. In some seed lots there was a high incidence of Fusarium spp. and Cercospora kikuchii. In these lots, there was response to the fungicidal seed treatment in the laboratory and the results obtained were similar to those in the greenhouse, where conditions were favorable for a rapid germination and unfavorable for the development of the fungus. In those lots in which the germination was not improved by the seed treatment, it was found, through the tetrazolium test, that the problem was caused by the action of one or more of the following factors: mechanical damage, moisture deterioration and stink bug injury. Based on the results, in was suggested that, instead of the standard germination test with paper towels, the sand emergence test should be made, or a treatment of the seed sample with and adequate fungicide before running the standard germination test.