This proceedings, "Lifeline Earthquake Engineering", contains papers presented at the Third U.S. Conference in Lifeline Earthquake Engineering held in Los Angeles, August 22-23, 1991. Besides reporting on the global state-of-the-art practices with lifelines that have been subjected to earthquakes, it presents an engineering analysis of various lifeline systems such as water/sewer, electric power, communication, gas and liquid fuel, and transportation lifelines. Specific topics included in these analyses are: Seismic hazard analysis, dynamic analysis of structures, damage assessment, risk and reliability, loss analysis, emergency response, and mitigation planning. An overview of lifeline earthquake engineering practices in the United States, New Zealand, and Japan are also presented. In addition, the results of a study of the 1989 Loma Prieta earthquake's effects on lifelines are discussed in depth in order to increase the understanding of the causes and effects of damage to lifelines.