The Tools for Integrated Management of Childhood Illness (TIMCI) project aims to evaluate the impact, cost-effectiveness, and operational requirements of introducing pulse oximetry supported by clinical decision support algorithms (CDSAs) into primary healthcare facilities for children under 5 years of age. The project's goal is to reduce morbidity and mortality among sick children attending primary care facilities in India, Kenya, Senegal, and Tanzania. By implementing this technology, TIMCI supports the rational and efficient use of diagnostics and medicines by healthcare providers. The project began on July 1, 2019, and is set to conclude on June 30, 2023. It is currently in the routine project/operational stage and targets children under 5 years old. The intervention involves software-based decision support focused on maternal and child health. Outcomes of the project include quantitative evidence from the multi-country mixed-method evaluation of pulse oximetry and CDSAs. The study protocol has been documented, highlighting its significance in improving childhood illness management. The project is funded by Unitaid.