A method capable of quantifying both cephapirin at a level of 20 parts per billion (ppb) and ceftiofur at a level of 50 ppb has been developed for raw bovine milk. Raw bovine milk is deproteinated with acetonitrile. The supernate is collected. Water is added to the sample, and the acetonitrile is removed under reduced pressure. The extract is loaded onto a conditioned C18 solid phase extraction column. The analytes are eluted with acetonitrile. Acetonitrile is completely removed during evaporation under a stream of nitrogen. The extract is filtered and analyzed using high performance liquid chromatography with ultraviolet detection measured at 290 nm. The analytes are separated from the matrix components using reversed-phase chromatography with an ion-pair mobile phase. The method has been validated at fortification levels equivalent to 10 to 40 ppb for cephapirin and 25 to 100 ppb for ceftiofur. Milk samples containing incurred residues of each drug have also been analyzed.