Sponsored by the Technical Council on Lifeline Earthquake Engineering of ASCE. When a magnitude 8.8 earthquake occurred off the coast of Chile on February 27, 2010, it affected 80 percent of Chile's population. Damage to lifelines was caused by strong ground shaking, permanent ground deformation, lateral spread, and a tsunami in the coastal areas of Bio Bio and Maule. Lifeline services were significantly disrupted for the first week, at a considerable cost to Chile's economy. This TCLEE report discusses in detail the effects of the earthquake, as observed by an ASCE-TCLEE team of civil engineers in April 2010. The team examined the performance of lifeline infrastructure systems, including transportation, ports, gas and liquid fuel, electric power, telecommunications, water and wastewater, and airports. An overview of each system's performance is provided, followed by a description of the damage to specific sectors or locations. An analysis of infrastructure interdependencies and resilience in Chile is included, as well as a report on emergency response, recovery, and social impact. This monograph will be of particular interest to civil engineers, managers, planners, emergency management personnel, and government officials charged with maintaining lifeline infrastructure systems to withstand earthquakes and other natural hazards.