This study aimed to determine the gaps of knowledge and practices of care of neonatal jaundice among Malaysian mothers. It was a cross sectional study of 400 mothers who attended the obstetric clinics or were admitted to the obstetric wards of a general hospital. They were surveyed with a structured set of questionnaire. The results showed that a majority (93.8%) of them knew about neonatal jaundice, and 71.7% knew that jaundice lasting more than 2 weeks was abnormal. However, only 34.3% of them were aware that jaundice appearing during the first 36 hours of life was abnormal. Less than 20% knew about glucose-6-phosphate dehydrogenase deficiency and that fetal-maternal blood group differences could cause jaundice. Although 71.7% and 69.7%, respectively, of the mothers knew that severe jaundice could cause death and brain damage, only 38.4% of them were aware that severe jaundice could result in hearing impairment. A very low proportion (27.1%) of them was aware that putting jaundiced infants under the direct sun could result in dehydration and worsening of jaundice. Out of a maximum score of 15, the mean maternal knowledge score was 7.4 (95% confidence intervals: 7.1, 7.7). Majority (83.1%) of the multiparous mothers with a past history of having children developing neonatal jaundice (n = 154) practiced placing their infants under the direct sun. This study revealed that there was a wide knowledge gap among Malaysian mothers on care of neonatal jaundice. Placing infants under the direct sun was still a common practice.