This paper has two objectives: First, to examine the frequency and conditions of occurrence of landslides during earthquakes due to soil liquefaction. In addition to discussing individual events during particular earthquakes, it is necessary, in order to evaluate the severity of the problem, to compile a list of known slides in which liquefaction has played a part. A review of the list shows that ... [Show full abstract] the slides have invariably been initiated by liquefaction of saturated sandy soils in a loose to medium dense condition as a result of earthquakes varying in magnitude from 5.5 to 8.5 points in Richter scale and at epicentral distances varying from several miles to hundreds of miles. This type of slide is indeed a serious problem in seismically active regions of the world. The second objective is to illustrate the importance of minor geologic and technical details in determining the occurrence and nature of landslides during earthquakes due to soil liquefactions. This is the Fourth Terzaghi lecture presented at the ASCE Structural Engineering Conference, at Seattle, Wash., May 8-12, 1967.