The symbiotic relationship between the soybean root and rhizobial root colonies and subsequent symbiotic nitrogen fixation is one of the most important physiological processes which occurs in the growth and development of the soybean plant. Soybean seed inoculation by Bradyrhizobium japonicum bacteria has long been established as an important practice in improving soybean yield on fields that have not seen soybean production in recent years. Yield increases of 40% have been observed in soybean inoculated by B. japonicum compared to non-inoculated in fields new to soybean production. However, with cost of rhizobial inoculation quite low, usually around $7/hectare, many farmers have adopted the practice of inoculating their soybean seed each year, to achieve greater root colonization than that provided by the indigenous rhizobial population, potentially resulting in increased nitrogen fixation and yields. The purpose of this project is to evaluate the effect on soybean growth and yield of a number of commercially available rhizobial inoculant products, and potential interactions with fludioxonil and metalaxyl-M fungicides. 7 different inoculant products have been tested at 6 different field sites throughout the lower penisula of Michigan. Preliminary data has provided generally positive results, with inoculated seed outyielding non-inoculated seed by an average of 5-7 bu./ha in most fields. Also, antagonism between soybean inoculant products and fludioxonil and metalaxyl-M fungicides has not been observed in fields that have previously been in soybean production. Yield differences between inoculated seed treated with fludioxonil and metalaxyl-M fungicides and non-inoculated seed treated with fludioxonil and metalaxyl-M fungicides have been similar to the above comparison between non-fungicide treated seed.