By 1990, the City of Los Angeles plans to have caused the abatement of seismic hazards in almost 8,000 unreinforced masonry buildings. No other U.S. city has undertaken such an extensive program or has actually enforced the abatement of so many structures. Recently, the Los Angeles City Council passed a six-month moratorium on evictions for the purpose of seismic upgrading. This is the first official indication of serious impacts arising from implementation of the ordinance. The objective of the research is to identify the impacts stemming from enforcement of the Los Angeles hazardous building ordinance and their possible implications for other U.S. cities. The focus will be on changes in building and land uses in neighborhoods with significant concentrations of unreinforced masonry buildings. Information from the Los Angeles experience will be made available to other researchers and summarized for use by public officials in other cities planning and implementing similar programs.