The feasibility of single-incision laparoscopic cholecystectomy (SIL-C) for patients with acute cholecystitis were evaluated based on the timing of operation after onset of symptoms. Sixty patients with acute cholecystitis who underwent SIL-C were divided into 2 groups according to the timing of operation: group E included 23 patients who underwent SIL-C within 72 hours, and group O included 37 patients who underwent SIL-C later. There were no statistical differences between group E and group O in clinicopathologic characteristics. Group E demonstrated significantly shorter operating time and less blood loss than group O. Although the incidences of additional port(s) requirements were not significantly different, 8 patients in group O required open conversion, indicating significantly higher rate. As group E demonstrated favorable surgical outcomes compared with group O, SIL-C for acute cholecystitis seems to be a feasible therapeutic procedure when performed within 72 hours as updated Tokyo Guidelines recommended.