Introduction: The 2017 surgical infection society (SIS) guidelines recommend 4 days of antibiotic therapy after source control for complicated intra-abdominal infections (cIAIs). Inappropriate exposure to antibiotics has a negative impact on outcomes in individual patients and populations. The goal of this study was to evaluate our institution's practice patterns and adherence to current antibiotic guidelines.Methods: Medical records from 2010 to 2018 for cIAIs were examined. Complicated appendicitis and complicated diverticulitis cases were included. Exclusion criteria included other etiologies of IAIs, pediatric cases, and cancer operations.Results: Fifty-nine complicated appendicitis cases and 96 complicated diverticulitis cases were identified. For all cases, antibiotic duration prior to publication of the SIS guidelines was significantly longer than post-SIS duration (appendicitis: 12.6 ± 1.1 days pre-SIS [n = 37] vs 9.0 ± 1.1 days post-SIS [n = 22], P = .01; diverticulitis: 15.1 ± 0.8 days pre-SIS [n = 49] vs 11.2 ± 0.5 post-SIS [n = 47], P = .04). Surgical management (SM) was associated with shorter duration of postsource control antibiotic exposure compared with percutaneous drainage (PD) for both appendicitis (SM 10.0 ± 1.2 days vs PD 13.4 ± 1.0 days, P = .02) and diverticulitis (SM 12.8 ± 1.5 days vs PD 16.0 ± 1.5, P = .07). Patients with complicated appendicitis received shorter duration of antibiotics when managed by acute care surgeons compared to general surgeons (8.4 ± 1.1 vs 11.9 ± 0.8, P = .02).Conclusion: Despite improvements after the SIS guidelines' publication, the antibiotic duration is still longer than recommended. Surgical intervention and management by acute care specialists were associated with a shorter duration of antibiotic exposure. [ABSTRACT FROM AUTHOR]