Background Bacterial infection is one of the leading causes of mortality in young infants globally. The standard practice to manage young infants with any sign of possible serious bacterial infection (PSBI) is in a hospital setting with parenteral antibiotics, which may not be feasible for majority of cases in most low resource settings. The World Health Organization developed a guideline on management of PSBI in young infants when referral is not feasible in 2016. Methods We conducted implementation research in selected communities in Zaria Local Government Areas of Kaduna State with an estimated population of 50,000 with the aim of understanding how to implement the WHO PSBI treatment guideline to achieve high coverage with low case fatality and treatment failure rates. Implementation was within the programmatic settings using existing health structure. We conducted policy dialogue with decision makers to adapt the recommendations to their social, cultural and programmatic context in Nigeria, held orientation meetings with program managers, built capacity of the health workers and supported the implementation within the health system. We supported a non-government organization to conduct community sensitization to promote care seeking and adherence to treatment advice. The research team collected data systematically on all young infants identified to have PSBI, the treatment they received and the clinical outcome.