PURPOSE: This was a cross sectional descriptive study to introduce the Infants Coma Scale (ICS), describe mental status of high risk infants using ICS and explore the relationships between ICS and clinical variables in infants hospitalized in a neonatal intensive care unit of a university hospital in Korea. METHODS: After ICS was developed and tested by the authors, a research nurse evaluated the mental status of the infants using the English version of ICS and obtained clinical information on the infants from their medical records. RESULTS: Data from 88 infants were analyzed. About 60% were male, 90% were preterm births, and 40% had pathologic abnormalities. Their mean gestational age was 32.4 (+/-3.50) weeks and the mean birth weight was 1,842 (+/-728.6) grams. The Cronbach's alpha for the ICS was .78. There was a statistically significant positive correlation between ICS total score and five clinical variables including gestational age, birth weight, 1 and 5 min Apgar scores and respiration status. CONCLUSION: Mental status is an important parameter in nursing assessment. ICS is a valid and reliable instrument, which clinicians can easily use to evaluate the mental status of high risk infants.