1) The present state of knowledge about the inheritance of milk yield and fat is summarised. 2) The design of the present investigation with material and method of work are briefly described. 3) From the analysis of 330 samples of milk and examination of the correlation table between the yield of milk and the yield of protein it is suggested: (1) that the yield of protein is inherited with the yield of milk. (2) that there are cases which may affect the yield of milk, without affecting the yield of protein.