This study aimed to clarify the prevalence of sarcopenia, which is characterized by loss of skeletal muscle mass and strength, and its relationship with nutritional state and quality of life (QOL) in patients with digestive diseases. This study enrolled 303 patients (187 men and 116 women with a median age of 70 y) having digestive diseases. Diseases were gastrointestinal in 99 patients, biliary/pancreatic in 93, and hepatic in 111. Skeletal muscle cross-sectional area was measured by abdominal computed tomography at the 3rd vertebra (L3) level. Sarcopenia was defined using the L3 skeletal muscle index and hand grip strength. Nutritional state was assessed by Subjective Global Assessment (SGA), Mini nutritional Assessment^®-Short Form (MNA^®-SF), anthropometry, and blood biochemistry. QOL was evaluated by Short Form-8^TM. Prevalence of sarcopenia was 32.0% in overall cases. The value was 22.2% in gastrointestinal disease, 36.6% in biliary/pancreatic disease, and 36.9% in hepatic disease. Advanced age, male sex, and advanced cancer state were associated with development of sarcopenia. Patients with sarcopenia had a significantly worse nutritional state according to SGA and MNA^®-SF than those without sarcopenia. In anthropometry, % arm muscle area, % calf circumference, and body mass index were significantly lower in the sarcopenic group. Serum albumin and hemoglobin were also significantly lower in the sarcopenia patients. QOL was more impaired in physical component subscales in sarcopenia patients than non-sarcopenia ones. Patients with digestive diseases frequently suffer from sarcopenia and this is associated with worsening of nutritional state and QOL in these patients.