Dissertation (MSc Pediatric Nursing)Umbilical cord care is among the essential newborn care practices recommended by the World Health Organization to reduce neonatal morbidity and mortality. There is still a gap of how much does practice of umbilical cord care has an impact on development of neonatal sepsis, also literature showed that young mothers had improper cord care.This study was carried in Tabora region with the aim of assessing the impact of practice of umbilical cord care among young mothers on development of neonatal sepsis. Health facility-based matched case -control study with a ratio 1:2, was carried out from January –March 2021 among 315 randomly selected young mothers aged 15 to 25 years with neonates aged between 7-28 days who were admitted in neonatal unit.Cases were young mothers whose neonates had sepsis and controls were mothers whose neonates had no sepsis. Interviewer-administered structured questionnaire and documentary reviewswere used to collect data which were then analyzed using descriptive and inferential statistics of which binary logistic regression model was employed and chi square, odds ratio and confidence interval were reported. The level of significance was set at less the 0.05. The umbilical cord care practice among young mothers was poor (68.6%) among cases and (54.8%) among controls.Multiple logistic regressionrevealedthat, hand hygiene(AOR=3.4,p=0.007),cord cleaning (AOR=2.6,p=0.027), covering the cord stump(AOR=2.5,p<0.001) and application of substance on cord (AOR=6.4,p=0.018) were significantly influencing neonatal sepsis neonates. Umbilical cord care practices is has a great impact on development of neonatal sepsis among young mothers. Hand hygiene,cleaning cord,covering cord stump and application of substances on cord were important factors that can contribute to development of neonatal sepsis. Hence, health facilities should have standard protocol for umbilical cord care which should be communicated to all young mothers and cares by health care providers (mainly nurses and midwives) during antenatal and postnatal care package delivery as this will discourage un -healthy practices .