A liquid chromatographic-tandem mass spectrometric (LC-MS/MS) multi-residue method for simultaneous quantification and identification of 37 anthelmintic veterinary drug residues (including benzimidazoles, macrocyclic lactones, and flukicides, levamisole, pyrantel and niclosamide) in milk has been developed and validated. For sample preparation, we used a simple modification of the QuEChERS (quick, easy, cheap, effective, rugged and safe) method, which was initially developed for analysis of pesticide residues. Anthelmintic residues were extracted into acetonitrile:methanol (9:1, v/v) using sodium chloride to induce liquid-liquid partitioning followed by dispersive solid phase extraction for cleanup. The extract was concentrated into dimethyl sulphoxide, which was used as a keeper to ensure that analytes remain in solution. Using rapid polarity switching in electrospray ionization, a single injection was capable of detecting both positively and negatively charged ions within a 15 min run time. The Limit of detection (LOD) and the Limit of quantification (LOQ) method ranged from 0.1 ng/g to 4.4 ng/g and from 0.3 ng/g to 14.6 ng/g, respectively. Validation of the developed method was based on international guidelines. Average recoveries ranged from 70% to 120%, except for 54.7% at 0.5× MRL (rafoxanide) and 69.0% at 0.5× MRL (closantel). The coefficient of variation for the described method was less than 15% over the range of concentrations studied. The result of the method was verified successfully by participation in a proficiency study for analysis of anthelmintic drugs.