Recently the function of the sirtuin family, named after their homology to the Saccharomyces cerevisiae gene silent information regulator 2 (Sir2), has received a lot of attention, as their beneficial impact on longevity was linked to their effects on metabolic control. All sirtuins require nicotinamide adenine dinucleotide (NAD(+)) for their deacetylase or ADP-ribosyl transferase activity, linking their function tightly to cellular energy levels. SIRT1, the founding member of the sirtuin family, modulates many aspects of glucose and lipid homeostasis in almost all key metabolic tissues. Other members including SIRT2, SIRT3, and SIRT4 are also implicated in various metabolic processes. Here, we review the recent data related to the role of sirtuins in the control of metabolic homeostasis and possible underlying molecular mechanisms.