Transcutaneous bilirubinometer(TcB) has been performed in patients who visited the outpatient clinic with jaundice, and the major factors and natural course of long-term hyperbilirubinemia were investigated. From January 2011 to December 2016, a review was made based on 61 electronic medical records that conform to the conditions of patients who visited outpatient clinic with neonatal jaundice. TcB values were measured to confirm the natural progress data of jaundice in the study sub-jects. We collected information on gestational age, birth weight, mode of delivery, Apgar score, patient and maternal blood type, feeding type and perinatal problems at outpatient visits. Feeding type was classified into breastfeeding, formula feed-ing, and mixed feeding. Total of 61 patients, 31 were born by vaginal delivery, and 30 were delivered by Caesarean section. 32 patients were male, and 29 were female. The mean gestational age was 38.07 ± 1.52 weeks and the mean birth weight was 3.04 ± 0.45 kg. Most of the infants were supplied by breastfeeding (39.3%) or mixed feeding (44.3%). The TcB values of the patients ranged from 10.0 to 19.0 mg/dL, when they visited for the first time with jaundice. The mean age was 11.64 ± 7.52 days and the mean body weight was 3.27 ± 0.66 kg. The range of TcB values at the next outpatient visit was 7.0 to 18.0 mg/dL. Initially measured TcB value was divided by 15.0 mg/dL and analyzed using Pearson Chi-square method, and the TcB value was significantly lower only in the delivery through Caesarean section (p=0.03). The changes in TcB values tend-ed to decrease during the follow-up period. The proportion of breast-feeding or mixed breast milk was slightly higher at 90.6% in the previous method of breastfeeding compared to those in the group with higher TcB values (p=0.009) (Table 3). When patients with mild jaundice visit the outpatient clinic and check the birth method and the main feeding method at the time of the visit, it is considered to be possible to reduce the number of examinations and to provide accurate information to the parents, thereby reducing the excessive interruption of breastfeeding.