In recent years, quality of life(QOL) has received much attention as a subjective health outcome by which to measure and adopt patient treatment. Few studies, however, have examined how the QOL of cancer patients differs depending on treatment methods, or the effects of immunotherapy on patients' QOL. Thus, this study aimed to reveal: 1) the differences in QOL between patients treated with immunotherapy and other methods, and 2) whether the QOL of cancer patients treated with immunotherapy improves in accordance with the duration of immunotherapy. Thirty-nine cancer patients receiving immunotherapy who completed a Quality of Life Questionnaire for Cancer Patients Treated with Anti-Cancer Drugs(QOL-ACD) were the subjects for statistical analyses. The result indicated that patients treated with immunotherapy exhibited a higher physical conditions score than did patients receiving chemotherapy (p<0.01). Given that the side effects of immunotherapy are fewer than those of chemotherapy, the results suggested that the presence of side effects during cancer treatment plays an important role in determining patients' QOL.