Aim. To compare clinical and endoscopic findings and standard therapy results in duodenal ulcer disease (DUD) patients with and without a history of perforated ulcer. Subjects and methods. One hundred and thirteen patients with recurrent DUD, including 61 patients with uncomplicated DUD (Group 1) and 52 patients with a history of perforated ulcer (Group 2) were examined. Esophagogastroduodenoscopy (EGDS) and 24-hour pH-metry were performed in addition to physical examination. Ulcer scarring was evaluated during control EGDS. Results. 75% of the patients with uncomplicated DUD were observed to have classical pain syndrome and the pain was milder, more extensive, and food-unrelated in the patients who had sustained perforation. Decreased appetite was more common in uncomplicated DUD (35%). EGDS showed that complicated DUD was accompanied by a significantly higher detection rate of erosive esophagitis (20%), gastritis (52%), duodenitis (25%), multiple ulcers (28%), and larger ulcer sizes. 35% of the patients who had experienced duodenal ulcer perforation exhibited an inadequate antisecretory effect of standard omeprazole doses, which was followed by the increase in ulcer scarring time by an average of 1.2 days. Conclusion. In the patients with perforated DUD, the history was typified by less pronounced, more extended, and food-unrelated pain, esophageal and gastroduodenal erosive damages, multiple ulcerative defects, large ulcer sizes than in those with uncomplicated DUD, as well as resistance to standard omeprazole dose in one third of the cases, and delayed ulcer scarring.