Comparison between ethanol producing bacteria Zymomonas mobilis (strain CCM 3881 and CCM 3883) and commercial yeast (D2, Bc-16a) was made using glucose medium. While the differences between bacteria and yeasts in low glucose medium (85.5 g/dcm3) were not of statistical importance, ethanol yield and sugars utilization were higher for Z. mobilis on medium with high concentration of glucose (150-250 g/dcm3). The bacteria growth was less inhibited by alcohol in the medium than yeasts. The bacteria biomass needed for 1 dcm3 ethanol production was from 2 times (glucose medium 85.5 g/dcm3) to 3-4 times (241 g glucose in 1 dcm3 medium) less than yeasts.