Diagnosis of alcoholism is very important, given its high prevalence and possibility of influencing the disease course. For this reason, the so-called biological markers of alcoholism are useful. These are analytic parameters that alter in the presence of excessive alcohol consumption. The two most relevant markers are the gamma-glutamyltranspeptidase and carbohydrate deficient transferrin. With this clinical comment, we aim to contribute to the knowledge of these tests and promote its use in the clinical practice.