On Jan. 17, 1995, the Hanshin-Awaji district was struck by the most destructive earthquake ever to occur in Japan. It is commonly believed that acute emotional stress such as that caused by an earthquake can trigger acute myocardial infarction (AMI). The objective of this study was to evaluate the effect of the quake stress on the onset of AMI in our district. The number of patients with AMI during the first 4 weeks after the quake increased by about 3.5-fold. The mean age of patients was 72.5 +/- 2.8 years, and the proportion of women (53%) was significantly greater than in the preceding years. The proportion of patients without prodromal angina pectoris was 53%. The mean post-traumatic stress disorder reaction index score (n = 14) was 40.1 +/- 4.1, which indicates a severe stress level. The mean score in the women (45.9 +/- 4.7; n = 7) was significantly higher than that in the men (34.3 +/- 6.4; n = 7). We concluded that after an earthquake, severe emotional stress can trigger AMI, more often than normal in women.