Objective. Mortality and morbidity following perforated peptic ulcer (PPU) is substantial and probably related to the development of sepsis. During the last three decades a large number of preoperative prognostic factors in patients with PPU have been examined. The aim of this systematic review was to summarize available evidence on these prognostic factors. Material and methods. MEDLINE (January 1966 to June 2009), EMBASE (January 1980 to June 2009), and the Cochrane Library (Issue 3, 2009) were screened for studies reporting preoperative prognostic factors for mortality in patients with PPU. The methodological quality of the included studies was assessed. Summary relative risks with 95% confidence intervals for the identified prognostic factors were calculated and presented as Forest plots. Results. Fifty prognostic studies with 37 prognostic factors comprising a total of 29,782 patients were included in the review. The overall methodological quality was acceptable, yet only two-thirds of the studies provided confounder adjusted estimates. The studies provided strong evidence for an association of older age, comorbidity, and use of NSAIDs or steroids with mortality. Shock upon admission, preoperative metabolic acidosis, tachycardia, acute renal failure, low serum albumin level, high American Society of Anaesthesiologists score, and preoperative delay >24 h were associated with poor prognosis. Conclusions. In patients with PPU, a number of negative prognostic factors can be identified prior to surgery, and many of these seem to be related to presence of the sepsis syndrome