Trace-elements play an important role in human metabolism. Often overlooked by clinicians, they are mandatory to supply for the patient with parenteral nutrition. When it is deficient or excessive, inadequate provision of trace elements can lead to serious complication. The nutrition provider should monitor deficiency and toxicity of each trace element carefully. In Korea, five trace elements (Zinc, Copper, Manganese, Chromium, and Selenium) are commercially available. However, according to the up to date recommendation, their dosages are not adequate for patients with long term parenteral nutrition. In this review, I considered the adequate dosage of each trace element under specific conditions, and provided a guideline for monitoring of trace elements.