A prospective study was undertaken in patients with perforated peptic ulcer to ascertain which organisms were encountered and to assess what role the duration of peritoneal soiling plays in the flora encountered and whether the degree of peritoneal soiling, as judged by the surgeon, correlates with bacterial contamination. After assessing the degree of soiling, pus swabs were taken and aerobic and anaerobic cultures and antibiotic sensitivity tests were performed. The most common organisms encountered were Gram-positive cocci (47%) followed by Gram-negative organisms (33%). There was no statistically significant increased bacterial growth time elapsed up to 48 hours. Severe peritoneal soiling, as judged by the surgeon, did not imply greater contamination.