Over the past decade, many OECD countries have introduced new policies to tackle excessive waiting times for elective surgery with some success. However, in the wake of the recent economic downturn and severe pressures on public budgets, waiting times times may rise again, and it is important to understand which policies work.  In addition, the European Union has introduced new regulations to allow patients to seek care in other member states, if there are long delays in treatment.   This book provides a framework to understand why there are waiting lists for elective surgery in some OECD countries and not in others. It also describes how waiting times are measured in OECD countries, which differ widely, and makes recommendations for best practice. Finally, it reviews different policy approaches to tackling excessive waiting times. Some countries have introduced guarantees to patients that they will not wait too long for treatment. These policies work only if they are accompanied by sanctions on health providers to ensure the guarantee is met or if they allow greater choice of health-care providers including the private sector. Many countries have also introduced policies to expand supply of surgical services, but these policies have generally not succeeded in the long-term in bringing down waiting times. Given the increasing demand for elective surgery, some countries have experimented with policies to improve priorisation of who is entitled to elective surgery. These policies are promising, but difficult to implement.