Biomass growth of Saccharomyces cerevisiae DAUFPE-1012 was studied in eight batch fermentations exposed to steady magnetic fields (SMF) running at 23ºC (± 1ºC), for 24 h in a double cylindrical tube reactor with synchronic agitation. For every batch, one tube was exposed to 220mT flow intensity SMF, produced by NdFeB rod magnets attached diametrically opposed (N to S) magnets on one tube. In the other tube, without magnets, the fermentation occurred in the same conditions. The biomass growth in culture (yeast extract + glucose 2%) was monitored by spectrometry to obtain the absorbance and later, the corresponding cell dry weight. The culture glucose concentration was monitored every two hours so as the pH, which was maintained between 4 and 5. As a result, the biomass (g/L) increment was 2.5 times greater in magnetized cultures (n=8) as compared with SMF non-exposed cultures (n=8). The differential (SMF-control) biomass growth rate (135%) was slightly higher than the glucose consumption rate (130 %) leading to increased biomass production of the magnetized cells.