Based on preliminary analysis, cases and controls were similar in age and sex distribution. Similar proportions of cases and controls were inside buildings (74% and 80%, respectively) and outside buildings (26% and 20%, respectively) during the earthquake. For persons who were inside a building, risk factors included building height, type of building material, and the floor level the person was on. Persons inside buildings with seven or more floors were 35 times more likely to be injured. Persons inside buildings constructed of concrete or mixed materials were three times more likely to sustain injuries than were those inside wooden buildings. Persons at middle levels of multistory buildings were twice as likely to be injured as those at the top or bottom levels.