Background: Perforations complicate up to 5-10% of peptic ulcer diseases. Mortality following peptic ulcer perforation can peak 29%. Of the factors that influence the outcome of peptic ulcer perforation, treatment delay is most important and modifi able. This study reviewed delay and how it affected outcome in patients treated for perforated peptic ulcers at the Kenyatta National Hospital.Methods: Patient’s files for the period January 2002 to December 2007 were reviewed and direct interviews carried out for patients seen from January to December 2008. Data sought included patient demographics, clinical presentation, time from symptom onset to presentation at casualty, time from presentation at casualty to surgical treatment and the treatment outcomes. Data was entered using a structured data sheet /questionnaire. The effect of delay as a determinant of outcome was evaluated using univariate analysis.Results: One hundred and ninety three patients were evaluated. Twenty four patients (12.4%) died. Sixty one patients (31.6%) developed complications post-operatively. Thirty patients were reoperated for the complications. No patient treated within 24 hours died. Complications rate was 0 %, 1.5% and 29.5% for patients treated within 24 hours, 24-48 hours and after 48 hours respectively. Delay >48 hours was significantly associated with increased mortality (p value <0.001), morbidity (p value <0.001), and surgical site infections (p value <0.001). The mean length of hospital stay for patients with delay <48 hours and over 48 hours was 7.22 (+ 1.9) and 19.7 days (+ 19.1) respectively (p<0.001).Conclusion: Delay of more than 48 hours is associated with high morbidity and mortality. Efforts should be made to reduce the amount of pre-treatment delay to less than forty eight hours.