Grading of difficulty is needed for laparoscopic liver resection (LLR). Indications for LLR are expanding worldwide from minor to major resections, particularly in institutions having surgeons with advanced skills. If the degrees of surgical difficulty were defined, it would serve as a useful guide when introducing LLR and stepping up to the more advanced LLR. As no previous study has addressed the degrees of difficulty of various LLR procedures, we devised a practical scoring system for this purpose. We extracted the following five factors from preoperative information to score difficulty levels: (1) tumor location, (2) extent of liver resection, (3) tumor size, (4) proximity to major vessels, and (5) liver function. This difficulty index is comprised of the cumulative score for the five individual factors. There has not yet been a standard definition of difficulty. Our proposed scoring system might be a practical means of assessing the difficulty of LLR procedures. However, this system must be prospectively validated.