The number one cause of down-time on SMT lines is related to material, as either a shortage or a logistical misstep that fails to place the right quantity of the right material at the right location at the right time. From a business perspective, the downtime caused by material problems is often the largest unplanned cost in the manufacturing operation. This paper will review many factors that contribute to the fundamental issue behind the chaos of material related downtime: inventory inaccuracy, and the steps needed to resolve this crucial problem.