Newborn period is a transitional stage for independent adaptation from intrauterine to extrauterine life by maintaining respiration, temperature and nutrition. In general, the adaptability of the newborn is proportional to the gestational age(GA), so knowing the accurate GA is critical to develop nursing process in the newborn nursery. A newborn ma turity rating, a Ballard examination, has been used to measure GA by assessing the maturity of new-born. It consists a total of 12 items, which is the 6 items for the neuromuscular maturity and the 6 items for the physical maturity A total of 75 new-born were assessed for the maturity and GA using the Ballard examination. The results are follows : 1) The score of each item of Ballard examination is propotional to GA using the Ballard examination as well as LMP. 2) There was a greater positive relationship between neuromuscular, physical and total maturity, and the GA measured by Ballard examination, than the GA measured by LMP. 3) Any stressful environment to the newborn could influence to the maturity of newborn. In summary, the study showed the Ballard examination Is more reliable and clincially feasible method to measure the accurate G4 compared to the GA by LMP. Therefore, it suggests the application of Ballard examination to measure the new born maturity and GA is beneficial in developing nursing process. The expansion of the study with the variety of the subject characteristics nil on hance the clinical applicability of the examination.