Gastrointestinal (GI) symptoms such as nausea, vomiting, abdominal pain, and diarrhea are common in patients with advanced liver disease. Changes of the GI function can be caused by malabsorption, GI motility disturbances, small intestinal bacterial overgrowth (SIBO), or various effects of metabolic derangement due to liver cirrhosis. Hepatocelluar carcinoma (HCC) and liver cirrhosis often share similar symptoms and signs. However, it is still unknown whether GI complaints in patients with HCC result from GI dysmotility. Herein, we report a case of GI dysmotility and SIBO in a patient with HCC and chronic HBV hepatitis. A 52-year-old man came to our hospital presenting with postprandial epigastric discomfort and abdominal bloating. Abdominal computed tomography showed diffuse infiltrative HCC. GI dysmotility and SIBO were found through studies including gastric emptying time, electogastrography, small bowel transit, antroduodenal manometry, and jejunal fluid culture.