Background Inpatient treatment of patients with colon diverticulitis represents a significant financial and clinical burden to the health care system and patients. The aim of this study was to compare patients with diverticulitis in the emergency department (ED), who were discharged to home vs admitted to the hospital. Study Design We reviewed all patients evaluated in the ED of a metropolitan health system, with the primary diagnosis of diverticulitis (ICD-9 562.11), from 2010 through 2012. Only patients diagnosed with CT and those with follow-up were included. Results We identified 240 patients; 132 (55%) were women and mean age was 59.1 years (SD 16.1 years). Imaging findings included extraluminal air (21%), pericolic or pelvic abscess (12%), free fluid (16%), and pneumoperitoneum (6%). One hundred forty-four (60%) were admitted to the hospital and 96 (40%) were discharged to home on oral antibiotics. Patients admitted to the hospital were more likely to be older than 65 years (p = 0.0007), have a Charlson comorbidity score ≥ 2 (p = 0.0025), to be on steroids or immunosuppression (p = 0.0019), and have extraluminal air (p < 0.0001) or diverticular abscess (p < 0.0001) on imaging. Median follow-up for all patients was 36.5 months (interquartile range 25.2 to 43 months). Among patients discharged from the ED, 12.5% returned to the ED or were readmitted within 30 days, with only 1 patient (1%) requiring emergency surgery, but not until 20 months later. Patients admitted to the hospital had similar rates of readmission (15%; p = 0.65). Conclusions Patients diagnosed with uncomplicated diverticulitis in the emergency room can be safely discharged home on oral antibiotics, as long as CT findings are included in the decision-making process. Patients with complicated diverticulitis on CT scan should be admitted to the hospital with surgical consultation.