The regulations that govern the production of certified organic produce in the United States are complex and cover all points of production from start (e.g., seed, input materials, origins of livestock) to finish (e.g., product handling, labeling, delivery). These regulations help ensure that organic produce is meeting a standard that everyone must follow. The Organic Materials Review Institute (OMRI) helps clarify this complex regulatory environment by focusing on one piece of certified organic production: input materials. Created by organic certifiers in 1997 to conduct this type of work, OMRI has built a reputation over the last 18 years as the leader in material review. This paper examines and explains the specific review criteria OMRI uses when evaluating the compliance of pesticide products for use in organic production under the U.S. Department of Agriculture's National Organic Program.