Traceability of foods has become very important problem respect to food quality and typicalness of foods. Cheeses' milk origin cannot be identified by the consumer and they are sold at different prices under various product names. Recently, this has caused the problem of 'adulteration'. The aim of this study is to determine the amount and origin of milk used in cheese production by using real-time PCR which has been used for identification of animal species in dairy products. In this study, 90 different cheeses offered for sale in Turkey of 30 brands from various sources such as cow, sheep and goat have been studied. At the end of the study, only 36.67% of samples were determined to be produced from 100% cow milk. In the remaining 1333%, a mixture of goat and sheep milk have been found. Only one sample of sheep cheese was produced from 100% sheep milk. In goat cheese samples, 16.67% of cheese was produced from 100% sheep milk and the origin of only 10% was identified as 100% cow milk. No linear relationship could be determined between chemical composition, fatty acids ratios and amount and origin of cheeses (P < 0.05). (C) 2016 Elsevier Ltd. All rights reserved.