This paper reports failure of gravity walls, masonry walls and reinforced-earth walls related to the 1999 Chi-Chi earthquake. After the earthquake, sliding and overturning failure of retaining structures were observed. The failures were most probably induced by the dynamic earth-pressure and lateral spreading of the uphill slope. A gravity wall built right above the Chelungpu fault was severely damaged by the vertical and horizontal movements of the fault. It is suggested not to build any retaining structure on top of an active fault.