Folates in milk are heat labile and methods used to protect these folates during sample preparation for microbiological estimation of this vitamin result in opaque solutions unsuitable for turbidimetric assays. This has necessitated the use of titrimetric assay for milk folates which are long and cumbersome. By the use of rennin precipitation of casein under conditions which preserve the folate activity, an optically clear solution is obtained which can then be used for turbidimetric assay. This method is described in this paper.