Background: The proportion of suicide attempts by infliction of abdominal stab wounds (ASWs) is higher in Japan than in other counties. There are few clinical reports on these wounds, especially hara-kiri wounds, which involve transversely cutting the abdomen. This study aimed to investigate Japanese patients with self-inflicted hara-kiri wounds and determine their characteristics and clinical features., Methods: We investigated 84 patients with self-inflicted ASWs who had been transferred to our hospital between April 1994 and March 2004. We recorded their characteristics and clinical features. They were then divided into two groups depending on their wound type, namely, simple stab wounds (SSWs) and hara-kiri wounds. The characteristics and clinical features of each group were then compared., Results: SSWs were frequently observed in the periumbilical and epigastric regions, whereas most hara-kiri wounds were observed in the middle abdomen. The rate of organ injury was 58.7% (44 of 75) for SSWs and 66.7% (6 of 9) for hara-kiri wounds; no significant difference was observed in this regard. SSWs resulted in injury to various organs, whereas hara-kiri wounds typically caused small bowel, mesenterium, omentum, and major vascular injuries. Small bowel and major vascular injuries had a significantly high incidence in hara-kiri wounds. The mortality rate caused by hara-kiri wounds was significantly higher than that caused by SSWs (1.3% vs. 22.2%)., Conclusion: The mortality rate caused by ASWs is relatively low. However, hara-kiri wounds might be a risk factor for death. Further, because hara-kiri wounds transversely cut the abdomen, they might be a risk factor for major vascular injury.