The objective of this study was to determine the nutritional support in patients treated in medical intensive care units (MICUs) by evaluating the extent of current nutritional support using the patient care plan and considering the association between nutritional status and the amount of nutrition supplied. From April to December 2010, 114 patients (age ${qeq}$ 18 years) admitted to the MICU and who underwent nutritional support for > 5 days were included. Descriptive statistics showed that the 114 patients received nutritional support within 1.2 ${pm}$ 0.7 days and for 16.2 ${pm}$ 11.7 days in the MICUs. The total delivered/required caloric ratio was 81.08 ${pm}$ 27.31%, and the protein ratio was 80.32 ${pm}$ 28.93%. Patients who received > 80% of required calories and protein showed improved nutritional status (p < 0.05). The results showed that adequate nutritional support is crucial to critically ill patients. We suggest early nutritional screening using simple tools such as periodic monitoring and management to recalculate nutritional status and nutritional requirements and nutritional support using a multidisciplinary method. Systematic nutritional support teams are needed to provide adequate nutritional support for patients in the MICU.