Background: Children are at increased risk for medication errors because of weight-based dosing and the need for diluting stock solutions, both of which may lead to calculation errors. Medication errors are reported in 0.15% to almost 6% of medication orders for children. Critically ill children may be at the greatest risk because of hemodynamic and respiratory instability, drug-drug interactions, disease-related abnormalities in drug clearance and volume of distribution, and renal or hepatic insufficiency. Objective: To describe the pattern of medication use in a tertiary care children's hospital intensive care unit (ICU), to determine the status of FDA labeling for the drugs used in the same ICU, and to determine the rate and types of medication errors reported in our ICU and whether the errors were related to factors such as length of ICU stay and the number of medications received. Methods: This prospective, observational study was conducted over a 6 month period in the 20 bed medical-surgical ICU of a free-standing children's hospital. Data collected included all medications prescribed, total number of admissions, patient's age, length of ICU stay, the number of drugs prescribed per patient, and the number of medication errors reported through a computerized database named Dr. Quality. Medication errors were categorized according to the National Coordinating Council for Medication Errors Reporting and Prevention Medication Errors Categories. In addition, the status of pediatric labeling for each drug was determined. Results: Six hundred thirty-nine patients were admitted to the ICU during the study period. The average length of stay was 4 days. Two hundred seven (32%) patients stayed for one day, while the longest stay was 62 days (1 patient). The total number of prescriptions ordered and dispensed during the study period was 8,025. Each patient received an average of 13 medications (49 drugs were given to one patient). The 3 most commonly prescribed medication groups in the ICU were analgesics/sedatives, antimicrobials, and gastrointestinal preparations. Five hundred fifty-seven (87%) patients received one or more analgesic or sedative drug. Eighty-one percent received at least one antimicrobial. Of the 8,025 medication orders, 17 (0.21%) medication errors were reported. One hundred different medications were dispensed during the study period, with only 33% labeled for use in children 0-18 years. The effects of ICU length of stay and number of medications prescribed per patient on the occurrence of medication errors could not be determined due to the small sample size. Conclusions: Patients in this ICU received a significant number of medications, of which only 33% were labeled for use in children. The rate of medication errors was 0.21%.