Recently, the number of patients with colorectal cancer has been increasing. Although most patients with early colorectal cancer have a good prognosis, in the case of recurrent or metastatic disease, the prognosis is poor and most patients will ultimately die of cancer. Furthermore, the conventional treatment, such as chemotherapy or radiation therapy, occasionally can not be continued due to reasons of toxicity and/or poor response. Therefore, novel therapeutic optional approaches based on immunotherapy are being explored at present. This review describes and sums up the principles and the longstanding problems of peptide vaccine therapy, and demonstrates the results of clinical trials with colorectal cancer peptide vaccine therapy, including the authors' personal appraisal. In conclusion, the future prospects of peptide vaccine therapy are described.