Antibiotic use in Mexico is characterized by high levels of consumption, irrational use in primary care services, and high rates of bacterial resistance that cause hospital infections. Changes are needed in the recommended method for reporting antimicrobial drug use, so that quantification can be carried out through drug utilization studies. Such studies, which make it possible to know which drugs are used in hospitals, require an accessible source of data on antimicrobial drug use with the least risk of biases, a single drug identification system, and the adoption of units of measure that can be extrapolated. The methodology developed by the WHO Collaborating Centre for Drug Statistics Methodology, based on the anatomical, therapeutic, and chemical classification (ATC) system and the daily defined dosage (DDD), is proposed. Despite its limitations, employing this methodology to monitor local antimicrobial drug use will make it possible to detect differences in usage patterns among institutions, and, especially, trends within a given institution. This would facilitate timely alerts about potential problems related to the use of antimicrobial drugs and the need for specific interventions.