Changes in cow’s milk composition and physical properties during the uninterrupted milking process. The chemical composition of milk determines the nutritional value and technological properties of milk and dairy products. Many studies have been performed on the chemical composition of milk, including fatty acid and protein profile, however a limited number of investigations have determined the changes in chemical composition of the milk during the milking process. Experiment were designed to study changes in milk chemical composition (i.e. fat, protein, casein, lactose, urea, citric acid, Total Solids (TS), Solids-Non-Fat (SNF), free fatty acids (FFA) as well as acidity, density, freezing point and somatic cell score) during the uninterrupted milking. Fifty two (455 samples) cows of 3 different breeds; with daily production 5-12 kg; were sampled during interrupted milking process. Representative sample were collected from each kg of milked liquid. There were significant (P≤0.01) changes in fat, FFA, lactose, TS and density of milk during milking. The concentration of fat, FFA, and TS shown increasing tendency with the course of milking, however, lactose and density presented opposite trends. Therefore, obtaining the whole quantity of milk from udder during the milking process, beside shaping the health status, is an indispensable step to produce milk of the highest quality in terms of its nutritional and technological value.