Mandates emphasizing student achievement have increased the importance of appropriate assessment techniques for students in general and special education classrooms. Informal reading inventories (IRIs), designed by classroom teachers, have been proven to be an efficient and effective way to determine students' strengths, weaknesses, and strategies in the areas of reading fluency, decoding, sight-word recognition, and reading comprehension. Although there are commercially designed IRIs on the market, teachers may often have neither the access nor the funds to purchase them. Additionally, teacher-designed tests provide curriculum-based assessment, thus allowing a direct link between evaluation and instruction. This article gives general and special education teachers working in K-8 classrooms information on why IRIs are important, reasons for creating such inventories specifically for their classrooms, as well as step-by-step instructions on how to create IRIs using quality literature. (Contains 5 tables and 2 figures.)