Seedling diseases of soybean and corn can cause significant losses through poor stand establishment and reduced plant vigor. Identifying the causal agent of seedling disease is not a simple process as the soil environment is complex and contains many thousands of microbe species but only a small portion of these actually cause disease. The primary causes of soybean seedling disease are Pythium spp., Phytophthora sojae, Rhizoctonia solani and Fusarium spp. In this study it was our objective to identify the predominant oomycete (Pythium and Phytophthora) species that cause soybean seedling disease. Only by understanding which pathogens cause disease are we are ultimately able to improve disease management.