Aim: Calcium is primarily stored in bones in the body. The increase in blood calcium level due to primary or secondary causes leads to several impairments of the gastrointestinal system like nausea-vomiting, and peptic ulcer (PU). In this study, we want to compare and analyse the difference in blood calcium levels of patients who underwent surgery for peptic ulcer perforation (PUP) and were diagnosed with PU by endoscopy.Material and Methods: Between May 2012-January 2017, patients’ data for PU disease were recorded and our study was planned retrospectively. Patients were seperated into two groups: Group1, who was operated for PUP; and Group2, who were administered medical therapy for PU. Blood calcium levels during admission, age, gender and drug history of patients were recorded. Study exclusion criteria were patients whose data were missing (n=113), patients who had metabolic bone disease, patients who had been using calcium channel blockers and who were administered anti-ulcer drugs.Results: Twenty-eight patients had PUP and 176 patients had PU disease. Group 1 had a lower mean age (p=0.017), and higher male gender rate (p<0.001). The mean calcium level of Group 1 was 9.7±0.6 mg/dl, while the mean calcium level of Group 2 was 8.8±0.7 mg/dl (p<0.001). Less than the cut-off value of 9.25, calcium showed a sensitivity of 78.6% and a specificity value of 73.1% between groups.Conclusion: In our study, we found that in patients with PU diagnoses, elevated levels of calcium found in controls may increase both stomach acidity and the risk of PUP