Introduction: Globally 11 million children passed away before celebrating their fifth birth day. The introduction of Integrated Management of New born and Child Illness protocol reduces under-five morbidity and mortality. However, the share of neonatal morality rate is increasing. As a result, united nations had set sustainable development goals to reduce national neonatal death rates through utilization of Integrated Management of New born and Child Illness protocol as main tool to 12 per 1,000 live births by 2030.but death rate from preventable cause increase due to low utilization of the protocol. Objective: The purpose of the research is to assess utilization of Integrated Management of Newborn and Child Illness protocol and associated factors among health care workers at health centers in South Gondor Zone, North-west, Ethiopia,2022. Methods: Institutional-based mixed study design was conducted from November to December 2022 in South Gondor Zone. A total of 422 health care workers were selected using computer random number generator . Data was entered by EpiData 3.1 software and analyzed using the SPSS version 25.0 statistical package. Binary logistic regression was used to identify the candidate for multivariable logistic analysis with p-value<0.2 and on multi-variable analysis P-value<0.05 with 95% confidence interval was taken as significant. For qualitative data, thematic analysis was conducted. Result: A total of 417 respondents were included for the final analysis of the study. The overall response rate was 98.8 % and mean age is 30.01years. The result showed that the proportion of IMNCI utilization was 63.1%. The odd of utilization of Integrated Management of New born and Child illness protocol among health workers who took training were 3.13 times higher as compared to those who did not take training [AOR=3.13,95% CI:1.594, 6.147]. Lack of drug reduce utilization of Integrated Management of New born and Child illness protocol by 75.7% as compared to the presence of the drug [AOR=0.243, CI95%:0.128,0.464]. Health care workers who always referring chart booklet during case management were 3.34 times more likely to utilize Integrated Management of New born and Child illness protocols [AOR=3.34, 95% CI: 1.99, 5.60] as compared to not referring the chart. Conclusion and Recommendation: utilization of Integrated Management of New born and Child illness protocol was low.Shortage of medical consumables and equipment attitude and training were identified factors that affect utilization of the protocol. Therefore, availing the necessary logistics and training for employees with regular supervision should be conducted with integration of sectors of woreda and zonal level. Keywords: Integrated management of newborn and child illness, Utilization, south Gondor zone.