A detailed analysis of the cell size, monitored as protein content, has been performed in glucose-limited continuous cultures, so as to obtain the values of the average protein content for various subpopulations at different cell cycle stages, as a function of the growth rate. Glucose metabolism appears to affect cell size, since there is an increase of the average protein content of the population when cells produce ethanol above the critical dilution rate. If the production of ethanol is forced at low growth rates by the addition of formate, the average protein content increases. These results indicate a link between glucose metabolism and cell size in budding yeast, as observed for mammalian cells.