Heavy metal toxicity represents an uncommon but clinically significant medical condition, which if unrecognized or inappropriately treated results in significant morbidity and mortality. Mercury is recognized as a potent and widely distributed toxicant in the global environment having ability to accumulate at various levels of food chain besides possessing ability to cross placental and blood–brain barrier. It has been seen that bacteria growing near mercury polluted sites have evolved various means of resistance based on the expression of different genes of mer operon against different forms of mercury. Microbe based remediation/detoxification of mercury is on forefront due to low cost and less health hazardous compared to physicochemical based strategies, which are cost intensive and hazardous to human health. However, strategies based on the modern aspects of biological technologies employing mer operon genes in different combination are needed to be designed for exploitation in the remediation of mercury completely from mercury contaminated environments.