Specifies a routine method (the Gerber method) for the determination of the fat content of milk and includes guidance on the determination of the appropriate capacity of the milk pipette and on the determination of the corrections to apply to the results if the milk is not of average fat content. The method is applicable to liquid milk, whole or partially skimmed, raw or pasteurized. With modifications, details of which are given, it is also applicable to milk containing certain preservatives, milk that has undergone the process of homogenization, in particular sterilized milk and ultra heat treated (UHT) milk, and skimmed milk.