The genetic analysis of ageing of the yeast Saccharomyces cerevisiae points to several processes important in determining life span. Among these, metabolic control plays a leading role. An examination of the molecular mechanisms underlying metabolic control of longevity has revealed two separate pathways. The retrograde response signals mitochondrial dysfunction to the nucleus resulting in gene regulatory changes that compensate. Nutritional status also modulates life span, adjusting metabolism to efficiently utilize energy resources, in a response that closely resembles the caloric restriction paradigm described in rodents. Although the retrograde response and caloric restriction are distinct pathways of life span extension, there appears to be some overlap of the longevity effectors under their control.