Three yeast cultures namely Saccharomyces cerevisia, Debaryomyces hansenii and Kluyveromyces marxianus were tested for their resistance to propolis extract.         Propolis aqueous extract (10% w/v) at the ratios 0.25, 0.50, 0.75 and 1.00% was examined. Changes in counts of yeasts were monitored after 7 days at 25^°C using synthetic medium. The effect of adding aqueous extract of propolis on the microbiological, chemical properties and organoleptic quality attributes of Labneh was investigated. Labneh was made from buffalo milk (5.5% fat) using 2% of mixed starter culture. The product was packaged in PVC (250g), stored at 6ºC for 3 weeks and analyzed weekly for chemical composition, microbial and organoleptic properties. The presence of 0.75 and 1.00% proplis was the most antimycotic for the tested yeast, while propolis 0.25% stimulated growth of the tested yeasts. No marked differences were recorded in total solids, fat and protein contents between the control and treated samples. The chemical composition of Labneh from different treatments was affected slightly during cold storage. However, the reduction in pH, and development of  diacetyl and Acetaldehyde were the highest in control, but lowest in Labneh with the highest propolis concentration. Higher propolis concentration proved to be effective in decreasing yeast, mould, lactic acid bacteria and total plate counts. Although the addition of  1.00% propolis could prolong the shelf life to to 21 days without any sings of yeast spoilage, but the Labneh was unaccepted according to its very sharp flavour and brownish color. It is recommended to add propolis (10% w/v) aqueous solution at the ratio of 0.25 and 0.50% to Labneh to prolong the shelf life and high scour sensory evaluation.