Public health surveillance systems in Rwanda are crucial for monitoring infectious diseases and other health threats. However, their reliability and effectiveness have not been systematically evaluated. A randomized field trial was conducted in two regions of Rwanda, with 10% of healthcare facilities randomly selected as controls. Data on disease incidence, reporting times, and system performance were collected over six months using standardised forms and statistical software. The study found a significant delay (mean difference = 5 days) in reporting infectious diseases from the point of diagnosis to official surveillance records in the intervention group compared to controls. Public health surveillance systems in Rwanda require improvement, particularly in reducing reporting delays. Investment should be prioritised in training healthcare workers and enhancing IT infrastructure to improve system reliability.