To the best of our knowledge, no available data with regard to changes in skeletal muscle mass for liver cirrhosis (LC) patients with esophageal varices (EVs) undergoing endoscopic therapy as a primary prophylaxis could exist. As endoscopic therapies, such as endoscopic injection sclerotherapy or endoscopic band ligation for EVs, accompany invasive procedure and patients with EVs receiving endoscopic therapies mostly rest in bed during hospitalization, clarifying these issues are clinically of importance. The purposes of this study were therefore to examine changes in skeletal muscle mass for LC patients with EVs undergoing endoscopic therapy as a primary prophylaxis and to identify pretreatment predictors which are associated with the amelioration in skeletal muscle mass. This is a subgroup analysis in our previous randomized controlled trial. A total of 51 LC patients with EVs were analyzed. Skeletal muscle mass was assessed using bioimpedance analysis (BIA). Skeletal muscle index (SMI) was defined as sum of skeletal muscle mass in body trunk and upper and lower extremities divided by height squared (cm2/m2) using data for BIA. We compared the changes in SMI at baseline and SMI at Day 50 after endoscopic treatment for EVs. Our study cohort included 33 males and 18 females with median (range) age of 62 (29–81) years. There were 31 patients with Child–Pugh A and 20 with Child–Pugh B. The median SMI for the entire cohort at baseline was 8.96 cm2/m2 (range, 5.87–13.11 cm2/m2), while the median SMI for the entire cohort at Day 50 was 8.83 cm2/m2 (range, 5.59–12.29 cm2/m2) (P = .9995). In baseline characteristics, prealbumin (P = .0477), branched-chain amino acid to tyrosine ratio (BTR) (P = .0056), and retinol-binding protein (P = .0296) in the increased SMI group (n = 15) were significantly higher than those in the nonincreased SMI group (n = 36). Multivariate analysis for the above 3 significant factors showed that only BTR was a significant prognostic pretreatment factor linked to the presence of increased SMI (P = .0235). In conclusion, pretreatment BTR level can be helpful for predicting increased SMI after endoscopic therapy as a primary prophylaxis for LC patients with EVs.