Yield reductions caused by S. glycines and P. glycinea (P. syringae) on soybeans were measured in the field on plants inoculated with either pathogen and by both in combination. The disease index based on percentage defoliation and percentage of remaining leaf area diseased on samples of 25 inoculated plants per plot ranged 65-78% for S. glycines, 60-69% for both combined, 46-62% for P. glycinea and 4-24% of the uninoculated check plants. Yield reductions of 17.9% for P. glycinea, 17.4% for S. glycines and 14.1% for both organisms combined were observed. Both yield and infection of inoculated plants differed statistically from uninoculated plants.