BACKGROUND: Interest in pharmacist participation in the multidisciplinary intensive care team is increasing. However, studies examining pharmacist interventions in the medical intensive care unit (MICU) are limited in Korea. The aim of this study was to describe the current status of pharmacist interventions and to identify common pharmacologic problems requiring pharmacist intervention in the MICU. METHODS: Between September 2013 and August 2014, a retrospective, observational study was conducted in the 22-bed MICU at a university hospital. Data were obtained from two trained pharmacists who participated in MICU rounds three times a week. In addition to patient characteristics, data on the cause, type, related drug, and acceptance rate of interventions were collected. RESULTS: In 340 patients, a total of 1211 pharmacologic interventions were performed. The majority of pharmacologic interventions were suggested by pharmacists at multidisciplinary rounds in the MICU. The most common pharmacologic interventions were adjustment of dosage and administration (n = 328, 26.0%), followed by parenteral/enteral nutritional support (n = 228, 18.1%), the provision of drug information (n = 228, 18.1%), and advice regarding pharmacokinetics (n = 118, 9.3%). Antimicrobial agents (n = 516, 42.6%) were the most frequent type of drug associated with pharmacist interventions. The acceptance rate of interventions was 84.1% with most accepted by physicians within 24 hours (n = 602, 92.8%). CONCLUSIONS: Medication and nutritional problems are frequently encountered pharmacotherapeutic problems in the MICU. Pharmacist interventions play an important role in the management of these problems.