Post-transplantation weight control is important for long-term outcomes; however, few reports have examined postoperative weight change. This study aimed to identify perioperative factors contributing to post-transplantation weight change. Twenty-nine patients who underwent liver transplantation between 2015 and 2019 with an overall survival of >3 years were analyzed. The median age, model for end-stage liver disease score, and preoperative body mass index (BMI) of the recipients were 57, 25, and 23.7, respectively. Although all but one recipient lost weight, the percentage of recipients who gained weight increased to 55% (1 month), 72% (6 months), and 83% (12 months). Among perioperative factors, recipient age ≤50 years and BMI ≤25 were identified as risk factors for weight gain within 12 months (P < .05), and patients with age ≤50 years or BMI ≤25 recipients gained weight more rapidly (P < .05). The recovery time of serum albumin level ≥4.0 mg/dL was not statistically different between the 2 groups. The weight change during the first 3 years after discharge was represented by an approximately straight line, with 18 and 11 recipients showing a positive and negative slope, respectively. Body mass index ≤23 was identified as a risk factor for a positive slope of weight gain (P <.05). Although postoperative weight gain implies recovery after transplantation, recipients with a lower preoperative BMI should strictly manage body weight as they may be at higher risk of rapid weight increase.