ABSTRACT Objective: to investigate the compliance to safety barriers adopted in the preparation and administration of intravenous drugs in Pediatric and Pediatric Intensive Care Units. Method: exploratory, observational descriptive study, conducted with the nursing team of a pediatric intensive care unit and a pediatric clinic of a large public hospital in Belo Horizonte, from August to November 2017. Results: the sample consisted of 334 opportunities to observe the preparation and administration of medications in pediatric patients. Most of the actions were performed by female professionals, nursing technicians and civil servants. The professionals did not perform all the necessary safety barriers in any of the procedures. The hygiene of the preparation site, disinfection of the ampoule, connection, conference of the drug/dose/route administered with the prescription and double checking of the drugs were those that had the lowest compliance. Conclusion: the study highlights the fragility regarding compliance to safety barriers in the preparation and administration of medicines, resulting in a risk to the safety of hospitalized children. Continued education based on good practice is believed to be an important strategy for security.