Public Private Partnerships (PPPs) are contractual arrangements between the public sector and the private sector- for profit and not-for profit firms - typically to design, build, finance and operate an infrastructure for the provision of a public service. PPPs are now employed for example for schools, hospitals, prisons, roads, motorways, bridges, IT services, accommodation, leisure facilities, military training and waste management. The workshop will aim to discuss some of the main characteristics of PPPs focusing on contractual issues and incentive problems.