Incisional hernias (IHs) are common complications after liver transplantation (LT) with a reported incidence of 1.7% to 34.3%. The purpose of this retrospective study was to evaluate the risk factors for IH development after LT with a focus on the role of immunosuppressive therapy during the first month after LT. We analyzed 373 patients who underwent LT and divided them into 2 groups according to their postoperative course: an IH group (121 patients or 32.4%) and a no-IH group (252 patients or 67.6%). A univariate analysis demonstrated that the following were risk factors related to IH development: male sex (P = 0.03), a body mass index ≥ 29 kg/m(2) (P = 0.005), LT after 2004 (P = 0.02), a Model for End-Stage Liver Disease (MELD) score ≥ 22 (P = 0.01), and hepatitis B virus infection (P = 0.01). The highest incidence of IHs was found in patients treated with mammalian target of rapamycin (mTOR) inhibitors (54.5%, P = 0.004). A multivariate analysis revealed male sex (P = 0.03), a pretransplant MELD score ≥ 22 (P = 0.04), and the use of mTOR inhibitors (P = 0.001) to be independent risk factors for IHs after LT. In conclusion, immunosuppressive therapy with mTOR inhibitors is an important independent risk factor for IH development after LT. To reduce the incidence of IHs, mTOR inhibitors should be avoided until the fourth month after LT unless their use is deemed to be strictly necessary.