Background: Health care organizations have redesigned existing and implemented new work processes intended to improve patient safety. As a consequence of these process changes, there are now intentionally designed "blocks" or barriers that limit how specific work actions, such as ordering and administering medication, are to be carried out. Health care professionals encountering these designed barriers can choose to either follow the new process, engage in workarounds to get past the block, or potentially repeat work (rework). Unfortunately, these workarounds and rework may lead to other safety concerns. Purpose: The aim of this study was to examine rework and workarounds in hospital medication administration processes. Methodology/Approach: Observations and semistructured interviews were conducted with 58 nurses from four hospital intensive care units focusing on the medication administration process. Using the constant comparative method, we analyzed the observation and interview data to develop themes regarding rework and workarounds. From this analysis, we developed an integrated process map of the medication administration process depicting blocks. Findings: A total of 12 blocks were reported by the participants. Based on the analysis, we categorized them as related to information exchange, information entry, and internal supply chain issues. Whereas information exchange and entry blocks tended to lead to rework, internal supply chain issues were more likely to lead to workarounds. Practice Implications: A decentralized pharmacist on the unit may reduce work flow blocks (and, thus, workarounds and rework). Work process redesign may further address the problems of workarounds and rework. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.