Amitraz, N´-(2,4-dimethylphenyl)-N-[(2,4-dimethylphenyl)- imino]methyl-N-methyl- methanimidamide, is an acaricide used to control the infections produced by the mites on cattle. Its use can cause the presence of residues in milk. For this reason, the analysis of amitraz residues in milk has received special attention in the scientific bibliography as opposed to milk analysis. On the other hand, amitraz is a very labile pesticide whose degradation products contain the 2,4-dimethylaniline moiety[1-3]. Thus, the analysis of all the residues containing this substructure is advisable. In this context, the aim of this work has been to develop a method to determine the amitraz total residues in milk.