Protons can be produced by depriving hydrogen atoms of electrons. When accelerated to a high energy level in an accelelator, protons form an ionized beam with strong penetration power. Unlike the conventional radiation beam, the proton beam has a unique dose distribution. It has a peak area (Bragg-peak) in which rapidly increasing doses are deposited at the end of the beam range defined by the particular beam energy. Therefore, proton therapy has an advantage in that a large dose of radiation can be focused only on the target, with a very limited irradiation of surrounding nontumor tissues. Thus the proton can be used to irradiate cancer while selectively avoiding normal tissues. Therefore, proton therapy is one of the modes of external radiation therapy having a potential almost equivalent to that of surgery in terms of local cure of the lesion.We previously reported that a large dose of proton irradiation can be safely given to patients with hepatocellular carcinoma (HCC) complicated with liver cirrhosis. The aim of this report is to show the efficacy of proton radiotherapy for tracing HCC and to clarify the long-term effects and QOL of this new therapy. Cumulative local tumor control rates were 98.1% for the 1st year, 90.9% for the 3rd year, and 88.1% at 3 years after the completion of irradiation. The overall survival rates were: 48.1% for 3 years and, 37.1% for 5 years. In regard to liver function: the Child-Pugh, Child Pugh A and chronic hepatitis groups had significantly higher survival rates than the Child B and C groups. The Child A and chronic hepatitis groups showed especially have an excellent survival rates such as; 60% for 5 yrs. The cumulative local tumor control rate was significantly higher in the proton groups (Mono and Combination) than in the 1-TAI group. The follow-up survival rate in the proton groups was also significantly higher than that in the 1-TAI group. No patients died of the adverse effects of proton therapy. Excellent quality of life (QOL) was maintained in all the patients treated with proton therapy during the treatment periods.