Studies using Saccharomyces cerevisiae revealed the existence of a unique family of proteins named Sirtuins. Sirtuins are highly conserved all the way from bacteria to humans. These proteins play important roles inside the cell, as nicotinamide adenine dinucleotide-dependent protein deacetylases. Sirtuins are major regulators of multiple cellular functions; they can modify the epigenetic landscape and are able to alter the proteome of the cell. Several studies have analyzed the role of sirtuins as a link between caloric restriction and aging. However, recent discoveries demonstrate new roles for these proteins. Sirtuins have also caught the attention of the biotechnology industry, and small molecule activators and inhibitors have been developed. The following review describes key aspects of sirtuin biology, presents the current situation of sirtuins in the biotechnology industry, and analyzes the emerging roles of sirtuins in cell metabolism, chromatin regulation, and cancer