Integrity of telomeres, the protective structures that cap the ends of eukaryotic chromosomes are crucial for the maintenance of chromosomal integrity and cell survival. Loss in telomere length homeostasis is a hallmark of various disease manifestations including cancer. Environmental or occupational exposure to heavy metal contaminants is known to disrupt this homeostasis. This study aims to substantiate the effects of heavy metal toxicity, particularly three heavy metal toxicants: arsenic, lead and cadmium on telomere length and to comprehend the mechanistic insights in depth. The mechanisms involved in telomere length alterations in response to heavy metal toxicity are still not clearly understood. Recent studies indicate epigenetic de-regulations in response to heavy metal toxicity and interestingly, telomere length is also regulated by epigenetic modifications. Environmental exposure induced epigenetic alterations might be one of the mechanism involved in telomere dysfunction. Telomeres are a prognostic marker in carcinogenesis, and hence further in-depth studies are indeed important in this field for future therapeutic purposes. © 2019, Archana Sharma Foundation of Calcutta.