N-Hibit™ is a seed-treatment that contains harpin protein, a compound that can stimulate plant defense responses. N-Hibit™ is now being sold in the United States for management of the soybean cyst nematode (SCN). Iowa State University evaluated the effects of N-Hibit™ seed treatment on soybean yield and SCN population densities in experiments at nine locations throughout Iowa. Experiments were conducted in Albert City, Mason City, and Manchester in northern Iowa; Cambridge, Farnhamville, and Urbana in central Iowa; and Council Bluffs, Crawfordsville, and Melrose in southern Iowa. The work was supported by the soybean checkoff through funds from the Iowa Soybean Association.