The study has been carried out in cow milk, in the milk of two goat and three sheep breeds. The milk samples were collected two times in a month for a 6-month period in the region of Mount Ida. The samples were analyzed for total protein, fat, total solid contents, pH and density. Protein profile analysis of the samples was performed by SOS-PAGE. The fluorescent probe binding method was used to characterize the surface hydrophobicity of the milk proteins. F-max, which is the number of surface hydrophobic sites was found to be significantly lower for all sheep milk samples compared to the goat and bovine milk samples. Furthermore. the PSH (protein surface hydrophobicity) values of the sheep milk samples were also lower than those of the other milk. These results indicate that casein structure of the sheep milk is more compact and contains less hydrophobic sites on the micelle surface. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.