Optimal surgical timing and operative technique in the treatment of acute cholecystitis are of major importance and are still debatable issues. We report the results of our study on the timing of surgery in a consecutive series of 163 patients treated in the emergency setting for acute cholecystitis over the period from 1998 to 2008. Early surgery and the partially downwards laparoscopic cholecystectomy technique provide a safe and effective way of treating these patients and preventing major complications. The mean time period between onset of symptoms and surgery was 69.2 hrs, with a median value of 53 hrs. The mean operative time was 63.9 min, with a conversion rate of 0.6% and a specific complication rate of 1.22%. The mean postoperative hospital stay was 3.2 days. The timing of surgery (measured in hours) and operative time (measured in minutes) were recorded and analysed to verify whether or not there was a statistically significant relationship between these two variables and establish the best timing for surgery. Our results show a linear relationship between operative time and the timing of surgery. Moreover, at the cut-off point of 57 hrs, the later subgroup (over 57 hrs) had a two-fold increase in operative time compared to the earlier subgroup. At more than 60 hrs approximately from the onset of symptoms, the pathological changes in the surgical target begin, with increasing rapidity, to present a troublesome challenge to the surgeon, making laparoscopic cholecystectomy for acute cholecystitis more difficult and less safe than when performed earlier.