The study explores the issues of data quality in the AIDS and TB grant process in Chad, focusing on the Project Management Unit of the Ministry of Public Health and Prevention. The aim is to analyze the impact of data quality on funding decisions for HIV and TB grants. The study, conducted using a mixed-methods approach, revealed a number of problems: inadequate monitoring, breaks in data collection tools, lack of a quality control mechanism, poor data transmission, lack of accountability and staff capacity. These shortcomings lead to poor planning and insufficient resources. Recommendations include reform of the data management system, creation of quality assurance teams, staff capacity building and regular external audits.