Abstract— Introduction: Children are our future and our most precious resources. Today’s children are the citizens of tomorrow’s world. The IMNCI case management component is mainly focused on the classification of the five most common causes of infant mortality (diarrhoea, pneumonia, malaria, measles and malnutrition), identification of treatment, accurate treatment or timely referral, counseling of the mother and giving follow-up care. IMNCI integrated treatment guidelines are devised to assist the health workers to assess the sick child by observing easily recognizable signs. Working through a color-coded system, the health worker classifies the sickness and takes the necessary steps such as urgent referral for medical treatment at a health Centre, medical treatment on the spot or advice for home management. Method & Material: An evaluative research approach and quasi-experimental research design was adopted. 150 nurses working in pediatric wards of selected hospitals at Patna were selected for the study by using purposive sampling technique. By using knowledge questionnaires, and competency checklists questionnaires. Results: The study reveals that out of 100% of nurses 3.3% of the nurses had good knowledge before Self-instructional module; majority of the nurses 60% had average knowledge; 36.6% of the nurses had poor knowledge. Whereas majority of the subjects 76.7% had good knowledge, 23.3% nurses had average knowledge after a Self-instructional module in IMNCI. In competency 51.7% had moderate on practice, 38.3% had adequate knowledge on practice, and 10% of the nurses had inadequate knowledge on practice before the Self-instructional module. Whereas majority of the nurses 83.3% had adequate knowledge on practice, 16.7% nurses had moderate knowledge on practice after the Self-instructional module on IMNCI. Conclusion: There is a positive co-relation observed between the level of knowledge and practice regarding Integrated Management of Neonatal and Childhood Illnesses among staff nurses. The study revealed that Self-instructional module improved the knowledge and practice regarding Integrated Management of Neonatal and Childhood Illness among Staff nurses.