Telomeres are specialized heterochromatin structures at the end of eukaryotic cell chromosomes, composed of specific deoxyribonucleic acid sequences which are known to play role in chromozomal replication, tumor beginning, aging and cell division. Telomerase is a reverse transcriptase enzyme that carries its own ribonucleic acid molecule, which is used as a template when it elongates telomerase. Because telomeres have increasingly gained attention due to their role in ageing, we aimed to review the literature about telomere shortening and telomerase during senescence.