The searches for new antimicrobial compounds to control the lactic acid bacteria in winemaking are based in the increasing global concern about the chemical preservatives restrictions and the development of super-resistant strains continuously exposed to sulfites in wineries for decades. The antimicrobial activity of the nisin as a biopreservative was studied for Bordô (Ives) and Niágara grape wines from Santa Catarina, Brazil. Measurements of antimicrobial activity were made by well-diffusion assays. From the eleven previously assessed strains of nisinsusceptible lactic bacteria (nisin concentration 1000 IU ml-1), four were selected for definitive assays with nisin (100 IU ml-1) dissolved in the wines. Positive results for inhibition were obtained for the four strains selected. Next, the direct inhibitory action was assessed in wines artificially inoculated and then treated with nisin. After 60 days of storage, there was reduction in the total bacterial population as compared to control, especially in Bordô (Ives) wine, while the physic-chemical parameters were not influenced by the nisin treatment. The inhibitory activity of nisin was not affected when it was dissolved in wine in the antimicrobial assays, and its potential utilization as biopreservative should be able to aid on the control of autochthonous microbiota, but further studies are required to conclude more precisely the nisin effects at long term in wines.