The detection of adulteration in the production of milk and other dairy products is crucial for economic reasons and consumer protection. In this study, yoghurts were produced from mixed milk (cow and sheep) in different ratios, and the percentage of sheep and cow milk was determined using TaqMan real-time polymerase chain reaction (PCR). 1% of cow milk was determined in the yoghurts and 0.01 ng of cow and sheep DNA was determined in sensitivity analyses. Therefore, TaqMan real-time PCR can be considered as a sensitive and reliable method for detecting cow DNA in yoghurt produced from mixed milk.