Transcutaneous bilirubin (TcB) nomograms have been developed for different populations. However, the TcB level, rate of rise and peak varies among countries and ethnicities. The aim of this study was to establish an hour-specific TcB nomogram for healthy term and late preterm Mongolian neonates during the first 144 h after birth. A total of 5084 TcB measurements from 1297 healthy neonates (gestational age ≥35 weeks, birth weight ≥2000 g) were obtained from October 2012 to October 2013. All measurements were performed using the Jaundice Meter, the JM-103 at 6 to 144 postnatal hours. Mongolian infants had the following characteristics: 27.1 % were delivered by cesarean section, 17.8 % had a birth weight >4000 g, and >90 % were being breastfed. TcB percentiles for each designated time point were calculated for the development of an hour-specific nomogram. TcB levels increased most rapidly in the first 24 h and less rapidly from 24 to 78 h, reaching a plateau after 78 h for the 50th percentile. TcB levels of Mongolian neonates for each time point were higher than those of previous studies. CONCLUSIONS The higher values of the TcB nomogram for Mongolian neonates may be due to their Asian ethnicity and exclusive breastfeeding. BACKGROUND • TcB nomograms for neonatal jaundice screening have been established for many countries and ethnicities. The pattern of the TcB nomogram varies by country and ethnicity. What is New: • A TcB nomogram for neonates of Mongolian ethnicity at 6-144 postnatal hours was created and it had higher values than those in previous studies.