Lactic acid fermentation is a natural method of antimicrobial food protection. Antagonistic activity ofLactobacillussp. bacteria, taking part in this process, is directed mainly against the same or other microorganisms. In this work we determine the impact of the presence of xylitol and galactosyl-xylitol on the antagonistic activity of 60Lactobacillussp. strains against indicator molds (Alternaria alternata,Alternaria brassicicola,Aspergillus niger,Fusarium latenicum,Geotrichum candidum, andMucor hiemalis) and yeasts (Candida vini). We used double-layer method to select antifungal strains ofLactobacillusbacteria and poisoned medium method to confirm their fungistatic properties. Additionally, we examined the inhibition ofAlternaria brassicicolabyLactobacillus paracaseiŁOCK 0921 cultivated with xylitol or galactosyl-xylitol directly on wild cherries. The presence of xylitol and its galactosyl derivative led to increase of spectrum of antifungal activity in most of the studied plant-associated lactobacilli strains. However, no single strain exhibited activity against all the indicator microorganisms. The antifungal activity ofLactobacillusbacteria against molds varied considerably and depended on both the indicator strain and the composition of the medium. The presence of xylitol and galactosyl-xylitol in the growth medium is correlated with the antifungal activity of the studiedLactobacillussp. bacteria against selected indicator molds.