Like Boeing, companies are increasingly focused on improving the quality of, and reducing defects in, their products, services, and activities. A rate of defects regarded as normal in the past is no longer tolerable, and companies strive for ongoing improvements in quality. Firms in industries as varied as construction (Skanska), aeronautics (Lockheed Martin), product development software (Dassault Systemes), and specialty food (Tate & Lyle) have set zero-defects goals. In this chapter, we focus on three types of costs that arise as a result of defects-spoilage, rework, and scrap-and ways to account for them. We also describe how to determine (1) the cost of products, (2) cost of goods sold, and (3) inventory values when spoilage, rework, and scrap occur.