Purpose To describe the voluntarily reported medications errors related to high-alert medications (HAM) in an adult Intensive Care Unit (ICU).Methods Retrospective observational study. We reviewed all the ICU medications errors related to HAMs reported to intranet-accessible, anonymous adverse event –reporting program by healthcare professionals over 36 months.Results Of the 268 medication errors reported, 102 (38.0%) were related to HAMs. Insulin (19.6%), followed of adrenergic agonist (15.7%), were the most frequent drug class associated with medication error. Prescription errors (54.0%) were the most frequent type of error, mainly related to the use of verbal orders that were not prescribed. Most of the reported medication error (63.7%) did not result in harm to the patient, being the alterations of plasma glucose levels the most frequent harm. All reported damages were transient and resolved with treatment, but all, of them prolonged the stay in ICU.Conclusion Medications errors related to HAMs in UCI are frequent, up to 38% of all the medications errors notified. In our study, most of them were related to insulin and adrenergic agonist. Although in most cases they are not related to permanent damage or death, in 34.3% of them there is an increase in ICU stay.