Abstrak: Salah satu masalah kesehatan yang sering dialami bayi adalah ikterus neonatorum yaitu suatu kondisi dimana kadar bilirubin > 10 mg %. Berdasarkan data rekam medik RSUD dr. H. Abdul Moeloek Provinsi Lampung jumlah neonatal yang mengalami ikterus sebesar 228 kasus (23,1%) dari 984 bayi yang bermasalah. Tujuan penelitian mengetahui faktor-faktor yang berhubungan dengan kejadian ikterus pada neonatus. Jenis penelitian kuantitatif melalui rancangan penelitian analitik dengan pendekatan case control. Populasi penelitian seluruh neonatus lahir hidup 0-28 hari sebesar 3032 neonatus dengan rata-rata ikterus / bulan sebesar 33 neonatus, besar sampel dengan perbandingan 1: 1 sehingga didapapat 33 kasus dan 33 kontrol, teknik sampling accidental sampling. Analisa data menggunakan univariat, bivariat dan multivariat. Hasil uji chi square didapat ada hubungan inkompatibilitas ABO (p value = 0,001 < 0,05), OR = 7,188, ada hubungan obat-obatan (p value = 0,012 < 0,05), OR = 4,241, ada hubungan kecukupan ASI (p value = 0,006 < 0,05), OR = 5,041, ada hubungan kejadian infeksi (p value = 0,013 < 0,05), OR = 4,103  dengan kejadian ikterus. Hasil uji regresi logistik berganda didapat variabel inkompatibilitas ABO yang paling dominan berhubungan dengan kejadian ikterus pada neonatus (p value = 0,001), OR = 41,167. Diharapkan bagi PUS dalam merencanakan program kehamilan agar memeriksakan golongan darah, ibu hamil tidak mengkonsumsi obat-obatan tanpa resep dokter terutama golongan obat ifluenza, antibiotik dan malaria serta teratur melakukan suntik TT dengan teratur dan menjaga kebersihan vulva hygiene.Kata kunci: Inkompatibilitas ABO, obat-obatan kecukupan ASI, infeksi, ikterusTHE FACTORS RELATED TO THE OCCURENCE OF ICTERUS IN THE NEONATALAbstract: One of the problems of health problems that are often experienced by babies are neonatal icterus that is a condition in which bilirubin levels> 10 mg%. Based on the data from medical records of dr. H. Abdul Moeloek Hospital of Lampung Province, the number of neonatal icterus are 228 cases (23.1%) out of 984 infants with problems. The purpose of this research is to find out the factors associated with the occurence of neonatal icterus. This is a analitic quantitative research with case control approach as the analytical research design. The population are icterus cases/month which are 33 people and population control are 66 people. Samples are calculated with ratio of 1:1, therefore there are 33 cases and 33 controls by using accidental sampling as the sampling technique. The data are analyzed using univariate, bivariate and multivariate analyzes.The result of chi-square test shows that there is an ABO incompatibility relationship with the occurence of neonatal icterus (p value = 0.001 <0.05), OR = 7.188, there is a relationship between the drugs and the occurence of icterus in neonates (p value = 0.012 <0.05), OR = 4.241, there is a relationship between the sufficient breastfeeding with the occurence of icterus in neonates (p value = 0.006 <0.05), OR = 5.041, there is a relationshipbetween infection in neonates with the occurence of icterus in neonates (p value = 0.013 <0.05), OR = 4.103. The results of multiple logistic regression test shows that the ABO incompatibility is the most dominant variables related to the occurence of icterus in neonates  (p value = 0.001), OR = 41.167. It is expected for pregnant women and their husbands to perform blood type before giving birth, not taking drugs without prescription especially ifluenza, antibiotics, and antimalaria drugs, mothers should directly breastfeeding the newborns, and take TT injections regularly.Keywords   : ABO incompatibility, drugs, sufficient breastfeeding, infection, icterus