Patients, health-care professionals and the public expect safe health care. The system, however, is not safe and patients are being harmed. Workplace and organizational conditions and human factors contribute to these harms and a system approach is needed to avoid them. In clinical microsystems (CMS), the frontline units of health care, staff and patients can make care safer by learning about their system, its processes, members and purposes. Approaches from patient safety should be integrated in the daily work of every member of the CMS to reduce risk, implement safe practices and learn from errors. We summarize methods for use in CMS and offer ideas for fostering a proactive culture of patient safety.