Over the last decades there is an increasing demand for consumption of functional foods which claim to provide health benefits. These days the majority of probiotic products are well established by the form of dairy products. However lactose intolerance, cholesterol substances and the increase of vegetarianism lead the research for commercial production, to find new, non-dairy, suitable media for probiotic products. Therefore, a preliminary research has been conducted regarding fermentation of Cornus mas L. juice with one potential probiotic microorganism (Lactobacillus paracasei K5) and one probiotic Lactobacillus plantarum ATCC14917 for functional beverage production. The viability of the aforementioned microorganisms was monitored during fermentation in different pH values, at 0 min, 24 h and during storage (5 ^oC) for 1,2,3 and 4 weeks. The results showed that Lactobacillus.plantarum ATCC 14917 and Lactobacillus paracasei K5 retained their viability at high levels (at  least 6 log cfu/ml) under storage at 5 ^oC for 4 weeks, which is considered as an important prerequisite for the characterization of the product as probiotic. Likewise the outcome showed that it is likely to produce a potential functional Cornus mas L. beverage with antioxidant activity (due to Cornus mas L. ingredients) and potential probiotic activities (due to the potential probiotic strains).