Objectives: Diverticular disease is a highly frequent condition and affects 50% of the population in the 9th decade in Western society. Acute diverticulitis is the most prevalent complication. The patients who are clinically stable and tolerate fluid should be hospitalized if fluid intake tolerance worsens, fever occurs, or pain increases. Bowel rest, intravenous fluid therapy, and empiric antibiotic therapy are the traditional treatments for patients admitted to the hospital. This retrospective study aimed to determine the parameters that will affect the outpatient or inpatient treatment of patients diagnosed with uncomplicated acute diverticulitis. Methods: Patients who presented to the emergency department with abdominal pain between January 2018 and December 2020 and were diagnosed with uncomplicated diverticulitis (modified Hinchey 1a) on computed tomography (CT) taken after intravenous contrast material shoot up were included in the study. Patient records were recorded retrospectively in the Excel file. After being seen in the emergency department, a comparison was performed between the inpatient group (Group 1) and the outpatient follow-up group (Group 2). Results: The study comprised 172 patients with acute uncomplicated diverticulitis (modified Hinchey 1a). While 110 (64.0%) patients were followed up and treated as inpatients (Group 1), 62 (36.0%) patients were followed up as outpatients (Group 2). There was no statistically significant difference between the two groups in terms of patients readmitted to the hospital in the first 30 days after discharge (both for outpatient follow-up in the emergency department and after treatment in the inpatient group). Conclusion: In this retrospective study, in which we evaluated the hospitalization criteria in uncomplicated Modified Hinchey 1a patients, it was found that patients can be safely treated as an outpatient if they have poor physical examination findings. Although there was no difference between the two groups in terms of hospital readmission after discharge and it was thought that follow-up of patients with Modified Hinchey 1a diverticulitis with outpatient oral antibiotic therapy might be reliable, prospective studies with larger numbers of patients are needed.