Ammonia concentrations in swine barns have an adverse impact on the health and safety of workers and animals. Ammonia also has the potential to cause eutrophication and acidification of water and soil. The impact of raw canola oil sprinkling and a low protein diet with fermentable carbohydrates (FC) on ammonia emissions of grower-finisher rooms was investigated. Ammonia emissions were reduced by 42% with the low protein diet with FC, and oil sprinkling did not affect the ammonia levels. Reducing the protein level and including FC in pig diets is an effective way to decrease ammonia emissions of swine buildings