Milk is a multinutrient fluid and it is the primary source of nutrition for human. It consists of 80% of proteins. The protein in the milk is classified into casein and whey protein. Milk protein consists of 80% of casein and 20% whey protein. The function of casein is to provide energy to human body. The name of casein is related to the family of phosphoproteins. These proteins are commonly found in the mammalian milk. This study deals with the precipitation of casein from the various milk samples such as cow milk, goat milk, buffalo milk and also the samples that availed from the market. The technique of precipitation of casein is used to predict the protein content in the milk samples.