Approximately 80% of the total soybean production in the United States occurs in the North Central States. Ten of the 12 most productive states are located in this region (Doupnik 1993). During a three-year period (1989- 1991) soybean production and disease loss for the North Central States was estimated at 13.17% or 236,730,000 bu (Doupnik 1993). At the current price of$7.00/bu that level of loss corresponds to a loss to the North Central States soybean growers of $552,370,000 per year! Soybean cyst nematode and Phytophthora root and stem rot are two major diseases of soybeans and often cause the greatest loss in production. Brown stem rot and the seed disease caused by Soybean Mosaic Virus also cause profit losses to the growers. Some soybean plants contain natural resistance or tolerance to these diseases which breeders have taken advantage of in developing new varieties. Biotechnology offers an array of tools that may help to control soybean diseases. Biotechnology can help us to clone the genes that provide natural resistance or tolerance and can help us to understand how these genes work. Once we understand how the resistance mechanisms work we can use these new technologies to engineer novel forms of resistance into the soybean. A team of researchers at Iowa State University have joined together, with collaborators from across the United States, to use molecular biological techniques to develop methods by soybean diseases can be controlled. This team studies the diseases caused by Soybean cyst nematode, Phytopthora root and stem rot, Brown stem rot, and Soybean Mosaic Virus, and attacks the problems of disease control by studying the pathogen as well as the plant. This paper will discuss some approaches used in the efforts to clone the genes conferring resistance to the fungal pathogen Phytophthora sojae, the pathogen causing Phytophthora root and stem rot.