Intra-abdominal pressure is the pressure's state of balance within the abdominal cavity when a patient is at rest. This pressure may vary during mechanical ventilation or spontaneous breathing. The objective was to establish the intra-abdominal pressure as a surgery predictor in patients with acute abdominal pain. From April to December, 2013, it was carried out a nested case-control study on patients with acute abdominal pain in the emergency room of a second level hospital. Thirty-seven patients fit the inclusion criteria; they all underwent surgery with a previous measurement of the intra-abdominal pressure. Based on the results of the anatomopathological study, we divided the patients into two groups: those with evidence of acute abdominal inflammatory process (n=28) (case group), and patients without evidence of acute abdominal inflammatory process (n=9) (control group). In the case group, 100 % of patients shown high intra-abdominal pressure with a p=0.01 (OR=5 [95 % CI=2.578-9.699]. In the case group, the mean intra-abdominal pressure was 11.46, and in the control group 9.2 (p=0.183). Abdominal pain requiring surgical intervention is directly related to intra-abdominal pressure>5 mmHg.