PURPOSE: Despite modern medication, peptic ulcer, patients often require emergency surgery for complications of peptic ulcer disease, and the mortality due to a perforated peptic ulcer still remains high. This retrospective study was conducted to evaluate the risk factors associated with mortality in patients undergoing surgery for a perforated peptic ulcer. METHODS: Two hundred and four consecutive patients (mean age: 45.8 years; range: 15~0 years) who underwent emergency surgery for a perforated peptic ulcer at the National Medical Center, between January 1991 and December 2000, were reviewed. RESULTS: The overall mortality rate was 5.9%. A univariate analysis of multiple clinical variables revealed old age (> or =65 years), duration of symptoms (> or =24 hours), NSAIDs or steroid use, comorbid disease, shock on admission, low hemoglobin (<10 g/dl), higher BUN (> or =20 mg%), higher creatinine (> or =1.5 mg%), gastric ulcer and simple closure to be significantly associated with mortality. However, a multivariate analysis showed that shock on admission, comorbid disease and old age (> or =65 years) were independent predictors of mortality. CONCLUSION: Shock on admission, comorbid disease and old age should be considered as significant prognostic factors of emergency surgery for a perforated peptic ulcer, and a comorbid disease and age as non modifiable factors. For that reason, prompt resuscitation is considered as the most effective therapy for reducing the mortality due to peptic ulcer perforation.