A case of carcinoid syndrome is presented. Pulmonary adenosquamous carcinoma with hepatic metastasis was found in a 60-year-old Japanese male who was complaining of fever, cough and haemosputum. After the treatment with 5-fluorouracil (5-FU) over 2 years, he was diagnosed as carcinoid syndrome on the appearance of facial flushing, face edema and watery diarrhea accompanied by high levels of 5-hydroxyindole acetic acid (5-HIAA) in blood and urine. Prednisolone, which was initially effective, was replaced by SMS201-995 due to the considerable dose increase of the former because its effect became insufficient during the course of the treatment. Clinical symptoms were improved by SMS201-995 and blood 5-HIAA level decreased gradually but markedly. Thus better results were obtained by SMS201-995 compared with prednisolone. These results imply that SMS201-995 is appreciated as an effective drug for treatment of carcinoid syndrome.