Telomerase is a common hallmark of cancer. Recent studies have shown promising developments in anti-telomerase cancer immunotherapy, using human telomerase reverse transcriptase (hTERT) as a tumor antigen. Vaccination, using hTERT peptides or adoptive transfer of hTERT-specific cytotoxic T lymphocytes, induces augmented tumor regression. CD8+ cytotoxic T lymphocytes, against various hTERT peptides, lyse hTERT-expressing tumor cells from multiple tissue origins. CD4+ helper T lymphocytes are also activated by peptides derived from hTERT. This article reviews the current and potential future applications of various hTERT peptide antigens as candidates for cancer vaccines, and explores the experimental challenges that needed to be faced to develop telomerase-based tumor vaccines to treat human cancer.