The present study deals with: 1-Evaluate the antifungal activity of selected lactic acid bacteria (4 Lactobacillus strains) against several species of yeasts and molds in laboratory agar media. 2- Demonstrate the efficacy of selected antifungal Lactic Acid Bacteria for preventing yeasts and molds growth on concentrated yogurt (Labneh), and study the stability of its antifungal activity during storage period. The fungi strains were used for the artificial contamination of labneh. 3-Antifungal activity assay: Two different methods (the overlay method and the disc assay method), were used to detect antifungal activity.