Minimally invasive surgery is one of the great innovations of health care in the 20th century. It promises to revolutionise surgery by allowing many more operations to be performed with minimal hospitalisation. Pressure from patients has caused many techniques to spread rapidly before they have been adequately assessed. This must be resisted, and policy makers must pay more attention to minimally invasive surgery to ensure that good assessments are made. The widespread use of minimally invasive techniques has important implications for hospitals and health workers. As more patients are treated on an outpatient basis, fewer hospital beds will be needed, and traditional operating rooms will have to adapt to a greater turnover of patients. Surgeons will have to acquire new operating skills, possibly requiring formal training and accreditation, and, as different specialties fight for control of new technologies, surgery may eventually be merged with internal medicine so that specialists will deal with organ systems. Postoperative care will have to be carried out in the community rather than in hospitals, and policy makers will need to reorganise their health systems to cope with these developments.