A large number of coastal and port structures, which have been constructed to prevent wave overtopping or beach erosion, have been damaged in Japan by severe marine climates caused by strong monsoons in winter and huge typhoons in summer to autumn. The reports of damaged structures, especially sea walls, for the past five years from 1992 to 1996 are selected from the annual books of damaged facilities edited by Port Bureau of Ministry of Transport in order to investigate the characteristics and causes of their damages. We have made statistical analysis for 197 cases of damaged sea walls. The analytical results show that scoring is a main cause of sea wall damages for each type of sea wall andtherefore the establishment of countermeasures against scoring is of great importance to reduce sea wall damages.