Objective <p>The objective of this study is to evaluate the efficacy and safety of laparoscopic ultrasonography (LUS) when applied during emergency laparoscopic cholecystectomy (LC) in patients diagnosed with severe calculous cholecystitis, and to compare its outcomes with those of standard LC performed after preoperative magnetic resonance cholangiopancreatography (MRCP).</p> Methods <p>Between January 2022 and June 2024, sixty patients with severe calculous cholecystitis were retrospectively identified and grouped based on their treatment approach. The Emergency Group (Group E, <i>n</i> = 30) comprised patients who underwent emergency LC with intraoperative LUS shortly after admission. The Routine Group (Group R, <i>n</i> = 30) included patients who underwent routine LC following MRCP confirmation of the absence of bile duct stones. Variables evaluated included demographic characteristics, operative details, intraoperative blood loss, time to bowel function recovery, length of hospital stay, hospitalization costs, and blood parameters (white blood cell count [WBC], C-reactive protein [CRP], total bilirubin [TBIL], direct bilirubin [DBIL], indirect bilirubin [IBIL], alanine aminotransferase [ALT], and aspartate aminotransferase [AST]) at baseline and on postoperative days 1 and 3.</p> Results <p>No statistically significant differences were observed between the two groups regarding operative duration, intraoperative blood loss, time to first bowel movement, or trends in laboratory parameters (<i>p</i> &gt; 0.05). However, patients in Group E demonstrated a significantly shorter overall hospital stay and reduced hospitalization costs compared with those in Group R (<i>p</i> &lt; 0.05).</p> Conclusion <p>The application of LUS during emergency LC was found to be a safe, effective, and practical therapeutic approach for patients with severe calculous cholecystitis. Its use was associated with shorter hospitalization duration and lower healthcare costs without an increased risk of perioperative complications.</p>