A newborn is an healthy infant born at term and should have an average birth weight, cries immediately following birth, establishes independent rhythmic respiration and quickly adapts to change environment. Newborn care refers to caring of the normal baby to ensure that the baby is made comfortable, fed and enhances early attachment process. Any deviation associated with negligence in appropriate care may lead to increased infant mortality rate. Global estimates of the distribution of direct causes of neonatal deaths indicate that severe infections, preterm birth and asphyxia are the three major killers of neonates. With this direction, the researchers assessed the effectiveness of planned teaching programme on newborn care among postnatal mothers in a selected hospital at Mangalore, Dakshina Kannada, Karnataka. Materials & Methods Quantitative approach was adopted in the present study. Pre-experimental, i.e., one group pre-test post-test design was used in this study. Purposive sampling technique was used for the selection of the sample. A close-ended structured knowledge questionnaire was used to assess the knowledge of postnatal mothers on newborn care. The study was conducted in selected Hospital at Mangalore with the sample size of 30 postnatal mothers. The data is analysed using descriptive & inferential statistics. Results The findings revealed that the pre-test knowledge level of knowledge of postnatal mothers was moderate 73%, poor 24% and good 3%. The post-test knowledge score (21.26±1.39) was higher than the pre-test knowledge score (13.1±3.61). Paired’ t test was showed that the gain in the knowledge was significant after administering planned teaching programme. Association between pre-test knowledge with demographic variables revealed that there was significant association between the pre-existing knowledge with demographic variable like education and newborn care.