Purpose Diverticulitis is a common cause of abdominal pain and CT scan is commonly used for its diagnosis in the emergency department (ED). The diagnostic performance of point-of-care ultrasound (POCUS) integrated into a clinical exam for diverticulitis is still not established. We evaluate the accuracy of clinical-sonographic assessment for the diagnosis of diverticulitis and whether POCUS could improve the selection of patients needing CT scan for complicated diverticulitis. Materials and Methods This is a multicentric observational study involving adult patients suspected of having diverticulitis presenting at 4 EDs. 21 sonographer physicians were asked to diagnose diverticulitis and complicated diverticulitis based on clinical-sonographic assessment. The final diagnosis was established by two reviewers, blinded to POCUS, based on data collected during the one-month follow-up comprehensive CT scan. Results Among 393 enrolled patients, 218 (55.5 %) were diagnosed with diverticulitis and 33 (8 %) had complicated diverticulitis. The time to diagnosis by the sonographer physicians was shorter compared to standard care (97 +/- 102 vs. 330 +/- 319 minutes, p < 0.001). Clinical-sonographic assessment showed optimal sensitivity (92.7 %) and specificity (90.9 %) for diverticulitis. However, the sensitivity (50 %) for complicated diverticulitis was low. The sonographer physician would have proceeded to CT scan in 194 (49.4 %) patients and the CT scan request compared to the final diagnosis of complicated diverticulitis demonstrated 94 % sensitivity. Conclusion Clinical-sonographic assessment is rapid and accurate for the diagnosis of diverticulitis. Even if POCUS has low sensitivity for complicated diverticulitis, it can be used to safely select patients needing CT.